Comparison of the oxidative stability of soybean and sunflower oils enriched with herbal plant extracts

The present study was conducted to determine and compare the oxidative stability of soybean and sunflower oils using differential scanning calorimetry (DSC). These edible oils were enriched with marjoram (Origanum majorana L.), thyme (Thymus vulgaris L.), and oregano (Origanum vulgare L.) extracts at three different concentrations and synthetic antioxidant (BHA). The fatty acid composition of studied oils was determined by gas chromatography mass spectrometry to evaluate the content of unsaturated fatty acids that are sensitive to oxidation process. Oil samples were heated in the DSC at different heating rates (4.0, 7.5, 10.0, 12.5, and 15.0 °C min^?1) and oxidation kinetic parameters (activation energy, pre-exponential factor, and oxidation rate constant) were calculated. The results showed that the oxidative stability of sunflower oil samples enriched with oregano extracts and soybean oil supplemented with thyme extracts was improved compared to samples without the addition of herbal plant extracts and the synthetic antioxidant.     

Quantitative Analysis of Phenolic Acids in Extracts Obtained from the Fruits of Peucedanum alsaticum L. and Peucedanum cervaria (L.) Lap

Peucedanum alsaticum L. and Peucedanum cervaria (L.) Lap. are, in common with all species belonging to the Apiaceae family, rich in coumarins and essential oils. Phenolic acids also present in the plant are very important pharmacologically, because of their broad spectrum of biological activity. A simple high-performance liquid chromatographic method has been developed for separation and quantitative analysis of the major phenolic acids in extracts obtained from the fruits of P. alsaticum and P. cervaria. Soxhlet extraction, ultrasound extraction, and accelerated solvent extraction under different conditions were used to find the most efficient extraction conditions. Optimum chromatographic performance was obtained with a C₁₈ column and acetonitrile—1% (v/v) aqueous acetic acid as mobile phase. Ferulic, p-coumaric, caffeic, vanillic, syringic, p-hydroxybenzoic, protocatechuic, chlorogenic, and gallic acids were investigated in the fruits of the plants. For all calibration plots linearity was good (R ² > 0.9991) in the ranges tested. The highest yields of most of the phenolic acids were achieved by use of accelerated solvent extraction. The predominant phenolic acid in the fruits of both plants was chlorogenic acid. The amounts, which depended on the method of extraction, were approximately 146 ± 1.616 and 109.92 ± 3.405 mg per 100 g dry weight for P. cervaria and P. alsaticum, respectively.     

Effect of <Emphasis Type="Italic">Rol</Emphasis> Genes on Polyphenols Biosynthesis in <Emphasis Type="Italic">Artemisia annua</Emphasis> and Their Effect on Antioxidant and Cytotoxic Potential of the Plant

Flavonoids are famous for their antioxidant capacity and redox potential. They can combat with cell aging, lipid peroxidation, and cancer. In the present study, Artemisia annua hybrid (Hyb8001r) was subjected to qualitative and quantitative analysis of flavonoids through HPLC. Rol genes transgenics of A. annua were also evaluated for an increase in their flavonoid content along with an increase in antioxidant and cytotoxic potential. This was also correlated with the expression level of flavonoids biosynthetic pathway genes as determined by real-time qPCR. Phenylalanine ammonia-lyase and chalcone synthase genes were found to be significantly more highly expressed in rol B (four to sixfold) and rol C transgenics (3.8–5.5-fold) than the wild-type plant. Flavonoids detected in the wild-type A. annua through HPLC include rutin (0.31 mg/g DW), quercetin (0.01 mg/g DW), isoquercetin (0.107 mg/g DW) and caffeic acid (0.03 mg/g DW). Transgenics of the rol B gene showed up to threefold increase in rutin and caffeic acid, sixfold increase in isoquercetin, and fourfold increase in quercetin. Whereas, in the case of transgenics of rol C gene, threefold increase in rutin and quercetin, 5 fold increase in isoquercetin, and 2.6-fold increase in caffeic acid was followed. Total phenolics and flavonoids content was also found to be increased in rol B (1.5-fold) and rol C (1.4-fold) transgenics as compared to the wild-type plant along with increased free radical scavenging activity. Similarly, the cytotoxic potential of rol gene transgenics against MCF7, HeLA, and HePG2 cancer cell lines was found to be significantly enhanced than the wild-type plant of A. annua. Current findings support the fact that rol genes can alter the secondary metabolism and phytochemical level of the plant. They increased the flavonoids content of A. annua by altering the expression level of flavonoids biosynthetic pathway genes. Increased flavonoid content also enhanced the antioxidant and cytotoxic potential of the plant.     

Comparison of different extraction methods for the determination of essential oils and related compounds from aromatic plants and optimization of solid-phase microextraction/gas chromatography

Different extraction methods for the subsequent gas chromatographic determination of the composition of essential oils and related compounds from marjoram (Origanum majorana L.), caraway (Carum carvi L.), sage (Salvia officinalis L.), and thyme (Thymus vulgaris L.) have been compared. The comparison was also discussed with regard to transformation processes of genuine compounds, particularly in terms of expenditure of time. Hydrodistillation is the method of choice for the determination of the essential oil content of plants. For investigating the composition of genuine essential oils and related, aroma-active compounds, hydrodistillation is not very useful, because of discrimination and transformation processes due to high temperatures and acidic conditions. With cold solvent extraction, accelerated solvent extraction, and supercritical fluid extraction, discrimination of high and non-volatile aroma-active components as well as transformation processes can be diminished, but non-aroma-active fats, waxes, or pigments are often extracted, too. As solid-phase microextraction is a solvent-free fully automizable sample preparation technique, this was the most sparing to sensitive components and the most time-saving method for the rapid determination of the aroma compounds composition in marjoram, caraway, sage, and thyme. Finally, solid-phase microextraction could be successfully optimized for the extraction of the aroma components from the plants for their subsequent gas chromatographic determination.     

Investigation of phytochemicals and antioxidant capacity of selected <Emphasis Type="Italic">Eucalyptus</Emphasis> species using conventional extraction

Eucalyptus species have found their place in traditional medicine and pharmacological research and they have also been shown to possess a large number of phenolic compounds and antioxidants. The present study sought to implement conventional extraction to yield maximal total phenolic content (TPC), total flavonoid content (TFC), proanthocyanidins, antioxidants, and saponins from E. robusta using different solvents. The most suitable extraction solvent was further employed for extracting phytochemicals from E. saligna, E. microcorys, and E. globulus to select the Eucalyptus species with the greatest bioactive compound content. The results emphasised the efficiency of water in extracting TPC ((150.60 ± 2.47) mg of gallic acid equivalents per g), TFC ((38.83 ± 0.23) mg of rutin equivalents per g), proanthocyanidins ((5.14 ± 0.77) mg of catechin equivalents per g), and antioxidants ABTS ((525.67 ± 1.99) mg of trolox equivalents (TE) per g), DPPH ((378.61 ± 4.72) mg of TE per g); CUPRAC ((607.43 ± 6.69) mg of TE per g) from E. robusta. Moreover, the aqueous extract of E. robusta had the highest TPC, TFC and antioxidant values among the other Eucalyptus species tested. These findings highlighted the efficiency of conventional extraction in extracting natural bioactive compounds from Eucalyptus species for pharmaceutical and nutraceutical applications.     

Investigation of Euphrasia rostkoviana Hayne Using GC–MS and LC–MS

Gas and liquid chromatography coupled with mass spectrometry was applied to solve difficulties and reinvestigate the serious matrix problems affecting analysis of the active compounds in Euphrasia rostkoviana Hayne. The main groups of compounds were obtained by extracting the herb stepwise with n-hexane, chloroform, ethyl acetate and methanol. Polyamide column chromatography facilitated further separation. Phenolic/flavonoid- and terpenoid-type molecules were studied by GC–MS, HPLC and LC–MS–MS. The β-sitosterol content of the herb was determined by gas chromatography with flame ionisation detection (GC-FID). Caffeic acid, chlorogenic acid, coumaric acid and flavonoid glycosides of apigenin, luteolin, rhamnetine (hexoside), kaempferol (both hexoside and rutinoside) and quercetin (rutinoside) were identified in the fractions of the methanolic extract.     

Multi elemental neutron activation analysis of popular medicinal plants used to prevent blood lipid disorders

In this study, five of popularly used medicinal plants as Cichorium intybus, Anethum graveolens seed, Thymus vulgaris, Fumaria officinalis and Hibiscus sabdariffa Syn: Hibiscus gossypifolius were prepared from Herbal Pharmacies in Tehran. The amounts of Al, Br, Ca, Cl, Cr, Fe, K, Mg, Mn, Na, V and Zn in samples were determined using instrumental neutron activation analysis. In this method, Tehran research reactor as a neutron source and relative INAA have been used as the analysis procedure. Highest levels of Cr (5 mg/kg), Ca (28316 mg/kg) and Mg (4134 mg/kg) were detected in Thymus vulgaris and F1umaria officinalis, respectively.     

Polyphenols,radical scavenger activity,short-chain organic acids and heavy metals of several plants extracts from “Bucharest Delta”

Some plants collected (Mentha aquatica, Bidens tripartita and Ambrosia artemisiifolia) from an unusual habitat developed in recent years in Bucharest (the so-called “Bucharest Delta”) and the contents of polyphenolic compounds, short-chain organic acids and heavy metals, and radical scavenger activity, were determined. 12 polyphenolic compounds and 7 short-chain organic acids were quantified using high-performance liquid chromatography and capillary electrophoresis; Mentha aq. extracts presented the highest levels of rosmarinic acid (1.58 mg g^?1) and ferulic acid (2.84 mg g^?1) and Bidens extracts presented the highest concentrations of chlorogenic acid (0.44 mg g^?1); the same extracts contain the most important levels of luteolin (0.52 mg g^?1) or other flavonoids. All the heavy metals detected in the plants studied were found in very low levels (the highest was Pb(II) in Mentha aquatica, (12.84 ± 0.48) µg kg^?1). The study sought to identify the active compounds and some contaminants in plants collected from the “Bucharest Delta” with the intention of eventual exploitation of the habitat and to enhance the knowledge of such human-modified ecosystems.     

Synthesis,biological evaluation,quantitative-SAR and docking studies of novel chalcone derivatives as antibacterial and antioxidant agents

In the present study, a series of chalcone derivatives including 17 new compounds were synthesised; their antibacterial activities against eleven bacteria, and their free radical-scavenging activities using DPPH were evaluated. All compounds showed significant antibacterial activities against both Gram-positive and Gram-negative bacteria. In particular, compound IIIf strongly inhibited Staphylococcus aureus (JMC 2151) and Enterococcus faecalis (CARS 2011-012) with MIC values of 6.25 µg mL^?1 and 12.5 µg mL^?1, respectively, which are comparable to that of the standard antibiotic, nalidixic acid. Compound IIIg also inhibited S. aureus with a MIC value similar to that of nalidixic acid (6.25 µg mL^?1). Furthermore, like nalidixic acid (MIC value of 25 µg mL^?1), compounds IIIa, IIIc and IIId inhibited Listeria monocytogenes (ATCC 43256) with MIC values of 25 µg mL^?1, 12.5 µg mL^?1 and 25 µg mL^?1, respectively. Quantitative structure-activity relationship (Q-SAR) studies using physicochemical calculations indicated that the antibacterial activities of chalcone derivatives correlated well with predicted physicochemical parameters (logP and PSA). Docking simulation by positioning the most active compound IIIf in the active site of the penicillin-binding protein (PBP-1b) of S. aureus was performed to explore the feasible binding mode. Furthermore, most of the compounds synthesised exhibited significant DPPH radical-scavenging activity, although compounds IIc and IIIc exhibited the greatest antioxidant activity with IC₅₀ values of 1.68 µM and 1.44 µM, respectively, comparable to that of the standard antioxidant, ascorbic acid (1.03 µM).     

Determination of polycyclic aromatic hydrocarbons in the needles of a Scotch pine (<Emphasis Type="Italic">Pinus sylvestris</Emphasis> L.), a biomonitor of atmospheric pollution

A procedure was developed for the determination of polycyclic aromatic hydrocarbons (PAH) in the needles of a Scotch pine (Pinus sylvestris L.), which is characterized by the simple and efficient sample preparation. The procedure involves the steps of the extraction of PAH with n-hexane on ultrasonic irradiation, the precipitation of concomitant cereous components from the extract on its cooling, the purification of the PAH fraction on a cartridge with silica gel (0.5 g), and the redissolution of the concentrated eluate in methanol. The quantitative determination of PAH (15 compounds including 13 priority) with the use of chromatography-mass spectrometry in the selective ion detection mode exhibits the interlaboratory precision of the results of the PAH determination V _Rl = 0.059–0.088 for the concentration of PAH in needles from 0.3 to 600 ng/g and a detection limit of 0.06 ng/g (signal-to-noise ratio = 3; mass of the sample for extraction was 10 g). The accumulation levels of PAH in the Scotch pine needles were presented; the needles were first studied as a biomonitor of atmospheric pollution over the southern part of the Baikal natural territory.     

Effect of drying methods on the content of natural pigments and antioxidant capacity in extracts from medicinal plants: a spectroscopic study

Medicinal plants are a significant source of biological active and health protective compounds. Post-harvest treatments can affect, in different ways, the content and biological activity of such compounds. One of the most common post-harvesting methods is drying. In this study, we investigated the effect of drying method on the content of natural pigments (chlorophylls, carotenoids and anthocyanins) and on the antioxidant capacity of two traditionally used herbs, the Melissa officinalis (lemon balm) and the Urtica dioica (stinging nettle) both of them landraces collected from plants grown in Nitra region, West of Slovakia. The freeze-dried samples of both herbs exhibited the highest content of chlorophyll a (7.55 ± 0.13 mg/g dry mass for lemon balm and 9.41 ± 0.17 mg/g dry mass for stinging nettle), chlorophyll b (3.12 ± 0.28 mg/g dry mass for lemon balm and 3.34 ± 0.24 mg/g dry mass for stinging nettle) and carotenoids (2.11 ± 0.24 mg/g dry mass for lemon balm and 2.62 ± 0.06 mg/g dry mass for stinging nettle). The content of chlorophylls and carotenoids correlated with the DPPH antioxidant (radical scavenging) capacity. Higher antioxidant capacity of the lemon balm extracts compared to nettle samples was attributed to the higher content of polyphenol compounds anthocyanins. Despite the higher cost, the freeze drying (lyophilisation) was recommended as the most suitable drying method, mainly for reasons of preserving maximum pigment content and antioxidant capacity.     

Acetone–Butanol–Ethanol Production from Waste Seaweed Collected from Gwangalli Beach,Busan, Korea,Based on pH-Controlled and Sequential Fermentation Using Two Strains

The optimal conditions for acetone–butanol–ethanol (ABE) production were evaluated using waste seaweed from Gwangalli Beach, Busan, Korea. The waste seaweed had a fiber and carbohydrate, content of 48.34%; these are the main resources for ABE production. The optimal conditions for obtaining monosaccharides based on hyper thermal (HT) acid hydrolysis of waste seaweed were slurry contents of 8%, sulfuric acid concentration of 138 mM, and treatment time of 10 min. Enzymatic saccharification was performed using 16 unit/mL Viscozyme L, which showed the highest affinity (K_m?=?1.81 g/L). After pretreatment, 34.0 g/L monosaccharides were obtained. ABE fermentation was performed with single and sequential fermentation of Clostridium acetobutylicum and Clostridium tyrobutyricum; this was controlled for pH. A maximum ABE concentration of 12.5 g/L with Y_ABE 0.37 was achieved using sequential fermentation with C. tyrobutyricum and C. acetobutylicum. Efficient ABE production from waste seaweed performed using pH-controlled culture broth and sequential cell culture.     

Bioethanol Production from Soybean Residue via Separate Hydrolysis and Fermentation

Bioethanol was produced using polysaccharide from soybean residue as biomass by separate hydrolysis and fermentation (SHF). This study focused on pretreatment, enzyme saccharification, and fermentation. Pretreatment to obtain monosaccharide was carried out with 20% (w/v) soybean residue slurry and 270 mmol/L H₂SO₄ at 121 °C for 60 min. More monosaccharide was obtained from enzymatic hydrolysis with a 16 U/mL mixture of commercial enzymes C-Tec 2 and Viscozyme L at 45 °C for 48 h. Ethanol fermentation with 20% (w/v) soybean residue hydrolysate was performed using wild-type and Saccharomyces cerevisiae KCCM 1129 adapted to high concentrations of galactose, using a flask and 5-L fermenter. When the wild type of S. cerevisiae was used, an ethanol production of 20.8 g/L with an ethanol yield of 0.31 g/g consumed glucose was obtained. Ethanol productions of 33.9 and 31.6 g/L with ethanol yield of 0.49 g/g consumed glucose and 0.47 g/g consumed glucose were obtained in a flask and a 5-L fermenter, respectively, using S. cerevisiae adapted to a high concentration of galactose. Therefore, adapted S. cerevisiae to galactose could enhance the overall ethanol fermentation yields compared to the wild-type one.     

Dual Stereochemical Control in Reaction of Di- and Trialkyl Phosphites with Aldimines

Stereochemistry of addition of di- and trialkyl phosphites to C=N compounds was investigated. Reactions of achiral dialkyl phosphites with chiral aldimines as well as that of chiral di-(1R,2S,5R)-menthyl phosphite with achiral aldimines result in low diastereomeric enrichment of the addition compound. Reaction stereoselectivity increased when supplementary chiral inductor was introduced to the reaction system. Reaction of di-(1R,2S, 5R)-menthyl phosphite with (S)-α-methylbenzylbenzaldimine proceeds as concerted asymmetric induction to form practically one diastereomer of N-substituted aminophosphonic acid. However, reaction of di-(1R,2S, 5R)-menthyl phosphite with (R)-α-methylbenzylbenzaldimine proceeded as not concerted asymmetric induction, and diastereomeric enrichment of the product was low. By chemical extrapolation, absolute configuration of compounds formed was established. Tri-(1R,2S,5R)-menthyl phosphite reacts with C=N compounds in the presence of boron trifluoride etherate to form aminophosphonic acid derivatives with the absolute configuration opposite to that appearing in the reaction of di-(1R,2S,5R)-menthyl phosphite with the same C=N compounds.     

Synthesis,DFT calculations and characterisation of new mixed Pt(II) complexes with 3-thiolanespiro-5<Emphasis Type="Italic">′</Emphasis>-hydantoin and 4-thio-1<Emphasis Type="Italic">H</Emphasis>-tetrahydropyranspiro-5<Emphasis Type="Italic">′</Emphasis>-hydantoin

Cisplatin is an anticancer drug widely used in the treatment of a wide range of solid tumours (head and neck, lung, bladder etc.), testicular and ovarian cancers. Because of its severe toxicity profile and spontaneous development of drug resistance in tumours, a number of Pt(II) complexes have been synthesised and tested for anti-tumour activity. Some of the investigations have focused on using ligands bearing donor atoms other than N (e.g., S, P, O). Two new mixed Pt(II) complexes of the general formula cis-[Pt(NH₃)LCl₂] where L is 3-thiolanespiro-5′-hydantoin and 4-thio-1H-tetrahydropyranspiro-5′-hydantom were synthesised. The complexes were studied by elemental analysis, melting points, IR and ¹H NMR spectra. The hybrid DFT calculations were used for optimisation of the structure geometries of the ligands III, IV and their Pt(II) complexes V and VI. The structural parameters so calculated, such as bond lengths and angles, are in good agreement with the experimental data for similar hydantoins and their platinum complexes. The results showed that the geometries of complexes V and VI are plane square and the bounding of ligands III and IV with platinum ions is effected by the sulphur atom from the cyclic ring. The complexes thus obtained were chemically examined in comparison with previously synthesised and published complexes of the general formula cis-[PtL₂Cl₂] (VII and VIII) with the same ligands. The new compounds V and VI, as well as the previously investigated complexes (VII and VIII), were analysed for cytotoxicity in vitro on SKW-3 and HL-60 human tumour cell lines. The results showed that all the complexes exerted concentration-dependent anti-proliferative activity.     

Release of Polyphenols Is the Major Factor Influencing the Bioconversion of Rice Straw to Lactic Acid

In this study, we found that p-coumaric acid (p-CA), ferulic acid (FA), and condensed tannins were released from rice straw during saccharification. The presence of polyphenols prolonged the lag phase and lowered the productivity of lactic acid. p-CA was identified as a key inhibitor. Tannins had a lower inhibitory effect than p-CA; FA had little inhibitory effect. Acid, alkaline, and ball milling pretreatments elicited different levels of polyphenol release from rice straw. Due to the different levels of polyphenol release in the pretreatment step, the enzymatic hydrolysates contained different concentrations of polyphenols. Compared with fermentation with a synthetic medium, fermentation with the hydrolysates of ball-milled rice straw provided much lower productivity and yield of lactic acid due to the presence of polyphenols. Removal of these compounds played an important role in lactic acid fermentation. When rice straw was alkaline pretreated, the hydrolysates contained few phenolic compounds, resulting in high productivity and yield of lactic acid (1.8 g/L/h and 26.7 g/100 g straw), which were comparable to those in a synthetic medium. This indicates that there is a correlation between removal of phenolic compounds and efficiency in lactic acid fermentation.     

Use of dodecanoyl isothiocyanate as building block in synthesis of target benzothiazine,quinazoline, benzothiazole and thiourea derivatives

Dodecanoyl isothiocyanate (I) reacts additively with anthranilic acid to afford derivatives of thiourea II and benzothiazine IIIin a one-pot reaction. The cyclisation of thiourea II was achieved using acetic anhydride to form quinazoline derivative IV. The heating of quinazoline IV in acetic anhydride or butan-1-ol gave quinazoline derivatives V or VI, respectively. Benzothiazine III underwent trans-acylation to benzothiazine VII in boiling acetic anhydride. The treatment of IV with hydrazine hydrate, anthranilic acid or ethyl carbazate afforded derivatives of triazoloquinazoline VIII, quinazolinoquinazoline XI or thiosemicarbazide X, respectively. The reaction of I with 2-aminophenol or 2-aminothiophenol afforded thiourea derivative XIII or benzothiazole derivative XIV, respectively. Most of the synthesised compounds bear a lauroyl (dodecanoyl) group (a hydrocarbon moiety). The structures of the synthesised compounds were confirmed by microanalytical and spectral data.     

Fumaric Acid Production from Alkali-Pretreated Corncob by Fed-Batch Simultaneous Saccharification and Fermentation Combined with Separated Hydrolysis and Fermentation at High Solids Loading

Production of fumaric acid from alkali-pretreated corncob (APC) at high solids loading was investigated using a combination of separated hydrolysis and fermentation (SHF) and fed-batch simultaneous saccharification and fermentation (SSF) by Rhizopus oryzae. Four different fermentation modes were tested to maximize fumaric acid concentration at high solids loading. The highest concentration of 41.32 g/L fumaric acid was obtained from 20 % (w/v) APC at 38 °C in the combined SHF and fed-batch SSF process, compared with 19.13 g/L fumaric acid in batch SSF alone. The results indicated that a combination of SHF and fed-batch SSF significantly improved production of fumaric acid from lignocellulose by R. oryzae than that achieved with batch SSF at high solids loading.     

Converting Chemical Oxygen Demand (COD) of Cellulosic Ethanol Fermentation Wastewater into Microbial Lipid by Oleaginous Yeast <Emphasis Type="Italic">Trichosporon cutaneum</Emphasis>

Cellulosic ethanol fermentation wastewater is the stillage stream of distillation column of cellulosic ethanol fermentation broth with high chemical oxygen demand (COD). The COD is required to reduce before the wastewater is released or recycled. Without any pretreatment nor external nutrients, the cellulosic ethanol fermentation wastewater bioconversion by Trichosporon cutaneum ACCC 20271 was carried out for the first time. The major components of the wastewater including glucose, xylose, acetic acid, ethanol, and partial of phenolic compounds could be utilized by T. cutaneum ACCC 20271. In a 3-L bioreactor, 2.16 g/L of microbial lipid accumulated with 55.05% of COD reduced after a 5-day culture of T. cutaneum ACCC 20271 in the wastewater. The fatty acid composition of the derived microbial lipid was similar with vegetable oil, in which it could be used as biodiesel production feedstock. This study will both solve the environmental problem and offer low-cost lipid feedstock for biodiesel production.     

Potentiality of independent component regression in assessment of the peaks responsible for antimicrobial activity of <Emphasis Type="Italic">Satureja hortensis</Emphasis> L. and <Emphasis Type="Italic">Oliveria decumbens</Emphasis> Vent. using GC–MS

Satureja hortensis L. and Oliveria decumbens Vent. are used in traditional medicine in the world due to its antifungal, antibacterial and antioxidant properties. In this study, the antimicrobial activities in Satureja hortensis L. and Oliveria decumbens Vent. essential oils against three microbial strains were evaluated by two different methods, including: disk diffusion method and micro-broth dilution assay [with minimal inhibitory concentration (MIC) between 0.025 and 0.500 µL/mL, and minimal lethal concentration (MLC) between 0.050 and 1.000 µL/mL] and qualitative analysis was performed by gas chromatography–mass spectrometry technique (GC–MS). The peaks potentially responsible for the antimicrobial activity in essential oils samples were indicated by some linear multivariate calibration techniques with different preprocessing methods. From the studied techniques, independent component regression (ICR) was preferred to exhibit the potential antimicrobial active compounds in Satureja hortensis L. and Oliveria decumbens Vent. essential oils because of its high repeatability, simplicity, and interpretability of the regression coefficients. Independent components (ICs) can give more chemical explanation than principal components (PCs), because independence is a high-order statistic that is a much stronger condition than orthogonality.