Antileishmanial diterpenoid alkaloids from Aconitum spicatum (Bruhl) Stapf

The crude extracts of tubers of Aconitum spicatum (Bruhl) Stapf were investigated for in vitro antileishmanial activity against Leishmania major. The dichloromethane extract at pH 2.5 showed antileishmanial activity with IC₅₀ value of 27.10 ± 0.0 μg/mL. Chromatographic purification of the dichloromethane extract led to isolation of three C-19 norditerpenoid alkaloids indaconitine (1), chasmaconitine (2) and ludaconitine (3). Compounds 3 and 2 showed antileishmanial activity with IC₅₀ = 36.10 ± 3.4 and 56.30 ± 2.1 μg/mL, respectively. Compound 1 was less effective (IC₅₀ > 100 μg/mL). The cytotoxicity of compounds 1, 2 and 3 studied against MCF7, HeLa and PC3 cancer cell lines and 3T3 normal fibroblast cell line did not show cytotoxicity at 30 μM.     

Antimicrobial compounds from root,stem bark and seeds of Melia volkensii

Three compounds, toosendanin (1), kulactone (2) and scopoletin (3), were isolated from either the root bark and/or the stem bark of Melia volkensii. Their structures were determined on the basis of spectroscopic data generated and by comparison with data from the literature. 1 and 2, isolated for the first time from M. volkensii, exhibited significant (p < 0.05) activity against Escherichia coli with minimum inhibitory concentration of 12.5 μg/mL, close to that of neomycin (6.25 μg/mL). The compounds also exhibited high activity against Aspergillus niger (MIC 6.25 μg/mL compared to 2.5 μg/mL for clotrimazole). Dichloromethane and methanol seed, hexane stem bark and methanol root bark extracts exhibited activities towards Escherichia coli, Staphylococcus aureus, Aspergillus niger and Plasmodium falciparum, respectively. Antimicrobial activity of the plant towards A. niger, P. falciparum and S. aureus is reported for the first time in the current work.     

Structures and bioactivities of seven flavonoids from Osmanthus fragrans ‘Jinqiu’ essential oil extraction residues

Osmanthus fragrans are well-known for their fragrance, but it is wasteful if to discard O. fragrans flower after extracting their essential oils. In this paper, we found that O. fragrans flower residues were rich in flavonoids. Six flavonoids and one phenylethanoid glycoside were isolated from the ethanol extract of O. fragrans flower residues, identified as quercetin (1), rutin (2), verbascoside (3), genistin (4), kaempferol (5), isorhamnetin (6) and naringin (7). In bioactivity study, kaempferol (IC₅₀ = 1.43 μg/mL) showed the best anti-inflammatory activity. Isorhamnetin, quercetin, kaempferol, verbascoside and rutin (the values of IC₅₀ were 18.30, 11.05, 16.88, 20.21 and 22.76 μg/mL, respectively) showed excellent DPPH free radical scavenging activity. Verbascoside performed relatively well at inhibiting the growth of both CT26 colonic carcinoma cells (IC₅₀ = 46.87 μg/mL) and HepG2 hepatocarcinoma cells (IC₅₀ = 30.58 μg/mL). In addition, quercetin and kaempferol showed strong anti-proliferation activity against HepG2 cells.     

A new antifungal and antiprotozoal bibenzyl derivative from Gavilea lutea

A new bibenzyl derivative (4), together with two glycosylated flavonoids (1 and 2), batatasin III (3) and the phenanthrene isohircinol (5) were isolated from the aerial parts of Gavilea lutea. Their structures were elucidated on the basis of spectroscopic studies including 1D and 2D NMR, UV, IR and HRESIMS. All isolated compounds were evaluated for their antifungal activity towards Candida albicans. The new compound 4 showed inhibitory activity with a MIQ of 50 μg. In addition, compound 4 exhibited a selective activity (IC₅₀ = 2.3 μg/mL) against Leishmania donovani.     

Activity-guided investigation of Carissa carandas (L.) roots for anti-inflammatory constituents

The present study was structured to investigate the anti-inflammatory potential of the extracts, fractions and compounds isolated from Carissa carandas (L.) roots. Bioassay guided fractionation of methanol extract based on inhibitory potential towards proinflammatory mediators (TNF-α, IL-1β and nitric oxide (NO)) led to the identification of stigmasterol (1), lupeol (2), oleanolic acid (3), carissone (4) and scopoletin (5) as potential anti-inflammatory agents. Carissone (4) (IC₅₀ = 20.1 ± 2.69 μg/mL) and scopoletin (5) (IC₅₀ = 24.6 ± 1.36 μg/mL) exhibited significant inhibition of NO production comparable to specific NO inhibitor (L-NAME; IC₅₀ = 19.82 ± 1.64 μg/mL) without affecting the cell viability. Also, 4 and 5 at a concentration of 30 μM were found to inhibit 41.88–53.44% of TNF-α and IL-1β. To the best of our knowledge, this is the first report displaying the anti-inflammatory effects of C. carandas (L.) roots, partially mediated by inhibition of TNF-α, IL-1β and NO.     

A new butenolide cinnamate and other biological active chemical constituents from Polygonum glabrum

Phytochemical investigation of the methanol extract of the aerial parts of Polygonum glabrum afforded one new natural product ( ? )-2-methoxy-2-butenolide-3-cinnamate (1) along with six known compounds, β-hydroxyfriedalanol (2), 3-hydroxy-5-methoxystilbene (3), ( ? ) pinocembrin (4), sitosterol-(6′-O-palmitoyl)-3-O-β-d-glucopyranoside (5), ( ? ) pinocembrin-5-methyl ether (6) and sitosterol-3-O-β-d-glucopyranoside (7). Compound 1 showed promising in vitro anti-HIV-1 activity against primary isolates HIV-1_UG070 (X4, subtype D) and HIV-1_VB59 (R5, subtype C) assayed using TZM-bl cell line with IC₅₀ in the range of 15.68–22.43 μg/mL. The extract showed TI in the range of 19.19–27.37 with IC₅₀ in the range of 10.90–15.55 μg/mL. Compounds 1, 3 and 4 exhibited in vitro anti-mycobacterium activity against Mycobacterium tuberculosis H37Ra with IC₅₀ values of 1.43, 3.33 and 1.11 μg/mL in dormant phase and 2.27, 3.33 and 1.21 μg/mL in active phase, respectively. Compound 4 was found to be the most active antiproliferative with IC₅₀ values of 1.88–11.00 μg/mL against THP-1, A549, Panc-1, HeLa and MCF7 cell lines.     

A new lumazine peptide penilumamide E from the fungus Aspergillus terreus

A new rare lumazine peptide, penilumamide E (1), together with 13 known compounds (2–14) were isolated from the fungus Aspergillus terreus. Their structures were identified by spectroscopic techniques. The relative configuration of 1 was confirmed by single-crystal X-ray diffraction analysis. Compound 10 exhibited antimalarial activity against Plasmodium falciparum with IC₅₀ values of 2.83 μg/mL. Compounds 4 and 6 showed weak cytotoxicity against cholangiocarcinoma (CCA) cell lines. In addition, 4 and 11 exhibited weak cytotoxicity against human hepatoma cell line.     

Xanthones from a lignicolous freshwater fungus (BCC 28210)

Abstract

Four xanthones (1?4) and a known compound, mansonone D (5), were isolated from the lignicolous freshwater fungus BCC 28210 (family, Chaetosphaeriaceae). The structures of these compounds were elucidated by extensive spectroscopic analysis. Among the isolated metabolites, compound 2 and the known mansonone D (5) displayed antimalarial activity against Plasmodium falciparum K1 with IC₅₀ values of 7.75 and 0.55?μg/mL, respectively. Compound 4 displayed antibacterial activity against Bacillus cereus with an MIC value of 6.25?μg/mL.     

Carbazole-pyranocoumarin conjugate and two carbazole alkaloids from the stems of Clausena excavata

A carbazole-pyranocoumarin conjugate, carbazomarin B (1), and two carbazole alkaloids, 6-methoxymukonidine (2) and 2-hydroxy-3-methoxycarbazole (3), together with 27 known compounds (4–30), were isolated from the stems of Clausena excavata. Their structures have been elucidated by spectroscopic analyses. Compound 2 showed moderate cytotoxicity to HuCCA-1, MOLT-3 and HepG2 cancer cell lines with IC₅₀ values of 15.09–28.50 μg/mL, but none to A549 cell line. Heptaphylline (6) and nordentatin (23) were found to show moderate cytotoxic activity against HepG2 cell line with IC₅₀ values of 12.33 and 11.33, respectively, while clausine K (27) exhibited strong cytotoxicity with IC₅₀ value of 1.05 μg/mL, better than a standard drug (etoposide, IC₅₀ 13.40 μg/mL).     

Antiplasmodial prenylated flavanonols from Tephrosia subtriflora

The CH₂Cl₂/MeOH (1:1) extract of the aerial parts of Tephrosia subtriflora afforded a new flavanonol, named subtriflavanonol (1), along with the known flavanone spinoflavanone B, and the known flavanonols MS-II (2) and mundulinol. The structures were elucidated by the use of NMR spectroscopy and mass spectrometry. The absolute configuration of the flavanonols was determined based on quantum chemical ECD calculations. In the antiplasmodial assay, compound 2 showed the highest activity against chloroquine-sensitive Plasmodium falciparum reference clones (D6 and 3D7), artemisinin-sensitive isolate (F32-TEM) as well as field isolate (KSM 009) with IC₅₀ values 1.4–4.6 μM without significant cytotoxicity against Vero and HEp2 cell lines (IC₅₀ > 100 μM). The new compound (1) showed weak antiplasmodial activity, IC₅₀ 12.5–24.2 μM, but also showed selective anticancer activity against HEp2 cell line (CC₅₀ 16.9 μM).     

Antimicrobial and antiparasitic activities of three algae from the northwest coast of Algeria

The objective of this study was to investigate the biological activities of Algerian algae, Sargassum vulgare, Cladostephus hirsutus and Rissoella verruculosa. Antimicrobial activity of the crude extracts and their fractions was assessed using the disc diffusion assay, the minimum inhibitory concentration and the minimum bactericidal concentration. Antiparasitic activity was studied in vitro against the blood stream forms of Trypanosoma brucei brucei and the intraerythrocytic stages of Plasmodium falciparum. Ethyl acetate (EA) fractions of the three tested algae showed more potent antimicrobial activity against S. aureus (7–14.5 mm) and B. cereus (7–10.75 mm), MIC values ranged from 0.9375 to 7.5 mg mL^?1 and MBC values > 15 mg mL^?1. Concerning the antiparasitic activity, EA factions of S. vulgare (IC₅₀ = 9.3 μg mL^?1) and R. verruculosa (IC₅₀ = 11.0 μg mL^?1) were found to be more effective against T. brucei brucei, whereas the three EA fractions were little active against P. falciparum.     

Structure activity relationship of bergenin,p-hydroxybenzoyl bergenin, 11-O-galloylbergenin as potent antioxidant and urease inhibitor isolated from Bergenia ligulata

Ethanol extract of the aerial parts of Bergenia ligulata was subjected to solvent–solvent separation followed by various chromatographic techniques that lead to isolation of bergenine (1), p-hydroxybenzoyl bergenin (2), 11-O-galloylbergenin (3) and methyl gallate (4) as major constituents. Ethyl acetate fraction showed a dose-dependent urease inhibitory pattern with IC₅₀ value of 54μg/mL. Structures of compounds 1 and 3 were established by XRD and 2, 4 by NMR. All these compounds were subjected to DPPH scavenging activity, reducing power assay and urease inhibitory activity. The EC₅₀ 7.45 ± 0.2 μg/mL and 5.39 ± 0.28 μg/mL values in terms of antioxidant and reducing power, respectively, were less for 3. Compounds 1–3 showed moderate to significant urease inhibitory potential with IC₅₀ 57.1 ± 0.7, IC₅₀ 48.4 ± 0.3 and 38.6 ± 1.5. Antioxidant activities and urease inhibitory potential were investigated and compound 3 was found to be the most active.     

Isolation and structural modifications of ananixanthone from Calophyllum teysmannii and their cytotoxic activities

Two naturally occurring xanthones, ananixanthone (1) and β-mangostin (2), were isolated using column chromatographic method from the n-hexane and methanol extracts of Calophyllum teysmannii, respectively. The major constituent, ananixanthone (1), was subjected to structural modifications via acetylation, methylation and benzylation yielding four new xanthone derivatives, ananixanthone monoacetate (3), ananixanthone diacetate (4), 5-methoxyananixanthone (5) and 5-O-benzylananixanthone (6). Compound 1 together with its four new derivatives were subjected to MTT assay against three cancer cell lines; SNU-1, K562 and LS174T. The results indicated that the parent compound has greater cytotoxicity capabilities against SNU-1 and K562 cell lines with IC₅₀ values of 8.97 ± 0.11 and 2.96 ± 0.06 μg/mL, respectively. Compound 5 on the other hand exhibited better cytotoxicity against LS174T cell line with an IC₅₀ value of 5.76 ± 1.07 μg/mL.     

Phytochemical analysis and antioxidant potential of the leaves of Garcinia travancorica Bedd.

Phytochemical analysis of the leaves of Garcinia travancorica, a hitherto uninvestigated endemic species to the Western Ghats of south India, resulted in isolation and characterisation of the polyisoprenylated benzophenones 7-epi-nemorosone (1) and garcinol (2) along with biflavonoids GB-1a (3), GB-1 (4), GB-2 (5), morelloflavone (6) and morelloflavone-7″-O-β-d-glycoside or fukugiside (7). The compounds were identified using various spectroscopic techniques, mainly through NMR and MS. The methanol extract and the biflavonoids 3, 4, 5 and 7 showed potential in vitro antioxidant activities. The IC₅₀ value of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of compound 7 was 8.34 ± 2.12 μg/mL, comparable to that of standard ascorbic acid (3.2 ± 0.50 μg/mL). In the superoxide radical scavenging assay, compound 7 gave IC₅₀ value of 6.95 ± 1.33 μg/mL close to standard ascorbic acid with IC₅₀ value of 5.8 ± 0.25 μg/mL. Validated HPTLC estimation revealed G. travancorica as a rich source of morelloflavone-7″-O-β-d-glycoside (7.12% dry wt. leaves).     

In vitro antiplasmodial and cytotoxic activities of sesquiterpene lactones from Vernonia fimbrillifera Less. (Asteraceae)

Due to the in vitro antiplasmodial activity of leaf extracts from Vernonia fimbrillifera Less. (Asteraceae), a bioactivity-guided fractionation was carried out. Three sesquiterpene lactones were isolated, namely 8-(4’-hydroxymethacrylate)-dehydromelitensin (1), onopordopicrin (2) and 8α-[4’-hydroxymethacryloyloxy]-4-epi-sonchucarpolide (3). Their structures were elucidated by spectroscopic methods (1D and 2D NMR and MS analyses) and by comparison with published data. The isolated compounds exhibited antiplasmodial activity with IC₅₀ values ≤ 5 μg/mL. Cytotoxicity of the compounds against a human cancer cell line (HeLa) and a mouse lung epithelial cell line (MLE12) was assessed to determine selectivity. Compound 3 displayed promising selective antiplasmodial activity (SI > 10).     

Coumarins and alkaloids from the roots of Toddalia asiatica

The EtOAc and MeOH extracts of the roots of Toddalia asiatica Lam. were investigated for the roots’ chemical constituents. Two new compounds including 2′R-acetoxytoddanol (1) and 8S-10-O-demethylbocconoline (3) as well as 15 known compounds were isolated. Compound 10 showed strong cytotoxicity against KB cells with an IC₅₀ value of 2.60 μg/mL, which is nearly equal to the ellipticine standard, but showed no activity against Vero cells. Alkaloid 3 displayed weak cytotoxicity against the KB cell line with an IC₅₀ value of 21.69 μg/mL.     

Antimalarial and cytotoxic activities of pregnene-type steroidal alkaloids from Holarrhena pubescens roots

The phytochemical investigation of an alkaloidal extract of Holarrhena pubescens roots led to the isolation and identification of a new pregnene-type alkaloid, mokluangin D (1), together with nine known steroidal alkaloids (2–10). The structure of the new metabolite was determined on the basis of spectroscopic analyses including 1D- and 2D-NMR spectroscopy and mass spectrometry. Compounds 3 and 4 showed potent antimalarial activity against Plasmodium falciparum K1 stain with IC₅₀ values of 1.2 and 2.0 μM, respectively, and showed weak cytotoxic activity against the NCI-H187 cell line with IC₅₀ values of 27.7 and 30.6 μM, respectively. The substituent groups at C-3 and the carbonyl group at C-18 are important for the activity against the P. falciparum K1 stain.     

New chemical constituents from the Piper betle Linn. (Piperaceae)

The phytochemical investigation of chloroform extract from Piper betle var. haldia, Piperaceae, leaves has resulted in the isolation of two new chemical constituents which were identified as 1-n-dodecanyloxy resorcinol (H1) and desmethylenesqualenyl deoxy-cepharadione-A (H4), on the basis of spectroscopic data 1D NMR (¹H and ¹³C) and 2D NMR (¹H-¹H COSY and HMBC) as well as ESI-MS, FT-IR and HR-ESI-MS analyses. Compounds H1 and H4 showed excellent antioxidant DPPH free radical scavenging activity with IC₅₀ values of 7.14 μg/mL and 8.08 μg/mL compared to ascorbic acid as a standard antioxidant drug with IC₅₀ value of 2.52 μg/mL, respectively. Evaluation of cytotoxic activity against human hepatoma cell line (PLC-PRF-5) showed moderate effect with the GI₅₀ values of 35.12 μg/mL for H1, 31.01 μg/mL for H4, compared to Doxorubicin^® as a standard cytotoxic drug with GI₅₀ value of 18.80 μg/mL.     

Two new bioactive triterpenoids from the roots of Colubrina asiatica

Abstract

Two new ceanothane triterpenes, 3,7-O,O-dibenzoyl ceanothic acid methylester (1) and 3-O-acetyl-7-O-benzoyl ceanothic acid methylester (2), along with nine known compounds (3–11), were isolated from the roots of Colubrina asiatica. The isolated compounds were identified by spectroscopic evidence. Compounds 1 and 2 showed antimalarial activity against Plasmodium falciparum with IC₅₀ values of 4.67 and 3.07?µg/mL, respectively. Compound 2 also showed antimycobacterial activity against Mycobacterium tuberculosis (MIC 6.25?µg/mL). In addition, compounds 1, 2, 10 and 11 showed cytotoxicity against three cancer cell lines (KB, NCI-H187 and MCF-7) with IC₅₀ values ranging from 8.32 to 46.72?µg/mL.     

A new lignan glycoside from the aerial parts and cytotoxic investigation of Uvaria rufa

Chemical investigation of the aerial parts of Uvaria rufa (Dunal) Blume collected from Vietnam yielded one new lignan glycoside, ufaside (1), along with six known compounds, oxoanolobine (2), ergosta-4,6,8(14),22-tetraen-3-one (3), catechin (4), epicatechin (5), daucosterol (6) and glutin-5-en-3-one (7). Their chemical structures were determined by using NMR, HR-MS spectroscopic analyses and in comparison with the reported data. A cytotoxic analysis of U. rufa herb extracts was performed for the first time using nine human cancer cell lines (MCF-7, MDA-MB-231, LNCaP, MKN7, SW480, KB, LU-1, HepG2 and HL-60) derived from different tumour types. Of these seven constituents, compounds 2 and 3 displayed moderate cytotoxicity against the human lung adenocarcinoma cell line (LU-1) with IC₅₀ values of 9.22 ± 1.02 μg/mL and 10.21 ± 1.16 μg/mL, respectively.