Cerebrosides and a monoacylmonogalactosylglycerol from Clinacanthus nutans

A mixture of nine cerebrosides and a monoacylmonogalactosylglycerol were separated from the leaves of Clinacanthus nutans. The structures of the cerebrosides were characterized as 1-O-beta-D-glucosides of phytosphingosines, which comprised a common long-chain base, (2S,3S,4R,8Z)-2-amino-8(Z)-octadecene-1,3,4-triol with nine 2-hydroxy fatty acids of varying chain lengths (C(16), C(18), C(20-26)) linked to the amino group. The glycosylglyceride was characterized as (2S)-1-O-linolenoyl-3-O-beta-D-galactopyranosylglycerol. The structures were established on the basis of the spectroscopic data and chemical reactions.     

Furofuran lignans and alkaloids from Clinacanthus nutans

One new furofuran lignan 2-methoxy-9β-hydroxydiasesamin (1), and four analogues (2–5), together with eight alkaloids (6–13), were isolated from the ethanol extract of the aerial part of Clinacanthus nutans. Their structures were elucidated by the detailed analysis of comprehensive spectroscopic data. All the compounds were isolated from the genus of Clinacanthus for the first time. In addition, lignans isolated from C. nutans was reported for the first time. Compound 1 exhibited modest activity against three human tumor cell lines Hela, MCF-7, and A549, with IC₅₀ values of 68.55, 60.00, and 59.17 μM, respectively.     

Anti-Inflammatory Effects of Phytochemical Components of Clinacanthus nutans

Recent studies on the ethnomedicinal use of Clinacanthus nutans suggest promising anti-inflammatory, anti-tumorigenic, and antiviral properties for this plant. Extraction of the leaves with polar and nonpolar solvents has yielded many C-glycosyl flavones, including schaftoside, isoorientin, orientin, isovitexin, and vitexin. Aside from studies with different extracts, there is increasing interest to understand the properties of these components, especially regarding their ability to exert anti-inflammatory effects on cells and tissues. A major focus for this review is to obtain information on the effects of C. nutans extracts and its phytochemical components on inflammatory signaling pathways in the peripheral and central nervous system. Particular emphasis is placed on their role to target the Toll-like receptor 4 (TLR4)-NF-kB pathway and pro-inflammatory cytokines, the antioxidant defense pathway involving nuclear factor erythroid-2-related factor 2 (NRF2) and heme oxygenase 1 (HO-1); and the phospholipase A₂ (PLA₂) pathway linking to cyclooxygenase-2 (COX-2) and production of eicosanoids. The ability to provide a better understanding of the molecular targets and mechanism of action of C. nutans extracts and their phytochemical components should encourage future studies to develop new therapeutic strategies for better use of this herb to combat inflammatory diseases.     

Chemical Constituents from the Butanol Fraction of Clinacanthus nutans Leaves

Chemistry of Natural Compounds -     

Metabolomic Approach for Rapid Identification of Antioxidants in Clinacanthus nutans Leaves with Liver Protective Potential

Antioxidants are currently utilized to prevent the occurrence of liver cancer in non-alcoholic fatty liver disease (NAFLD) patients. Clinacanthus nutans possesses anti-oxidative and anti-inflammatory properties that could be an ideal therapy for liver problems. The objective of this study is to determine the potential antioxidative compounds from the C. nutans leaves (CNL) and stems (CNS). Chemical- and cell-based antioxidative assays were utilized to evaluate the bioactivities of CNS and CNL. The NMR metabolomics approach assisted in the identification of contributing phytocompounds. Based on DPPH and ABTS radical scavenging activities, CNL demonstrated stronger radical scavenging potential as compared to CNS. The leaf extract also recorded slightly higher reducing power properties. A HepG2 cell model system was used to investigate the ROS reduction potential of these extracts. It was shown that cells treated with CNL and CNS reduced innate ROS levels as compared to untreated controls. Interestingly, cells pre-treated with both extracts were also able to decrease ROS levels in cells induced with oxidative stress. CNL was again the better antioxidant. According to multivariate data analysis of the ¹H NMR results, the main metabolites postulated to contribute to the antioxidant and hepatoprotective abilities of leaves were clinacoside B, clinacoside C and isoschaftoside, which warrants further investigation.     

Bioassay‐guided Isolation and Antioxidant Activity of Sulfur‐containing Compounds from Clinacanthus nutans

Clinacanthus nutans has been used in traditional herbal medicine for cancer prevention, but the specific bioactive compounds responsible for the observed activities have not been explored. Different polar solvents such as methanol, chloroform, ethyl acetate, and hexane were used for the extraction. The extracts, fractions, and isolated compounds were subjected to DPPH and ferric reducing antioxidant potential (FRAP) assays. Methanol extracts show significant free‐radical scavenging activity of 69.09% in DPPH and 56.49% FRAP. Purification of MeOH extracts afforded the fraction FB28 and two new sulfur‐containing compounds, named clinamide D and E ( 1 , 2 ). Compound ( 1 ) proved to be more active with an IC₅₀ value for DPPH radical scavenging of 118.27 ± 0.01 µg/mL and reduction of Fe³⁺–TPTZ complex of 386.24 ± 0.02, higher than that of the standard ascorbic acid. Sulfur‐containing compounds isolated from C. nutans is a potential natural antioxidant.     

Secondary Metabolites of Mahonia bealei

Chemistry of Natural Compounds -     

Secondary Metabolites of Litchi chinensis

Chemistry of Natural Compounds -     

Secondary Metabolites of Elaeagnus thunbergii

Chemistry of Natural Compounds -     

Secondary Metabolites from Magnolia kachirachirai

Investigation of the root bark of Magnolia kachirachirai led to the isolation of a new sesquiterpene, kachirachirain ( 1 ), and a new aporphine alkaloid, kachirachiranine ( 2 ), together with 20 known compounds, of which dimethyl 4,4′‐methylenebis(4,1‐phenylene)diurethane ( 3 ) was isolated for the first time from a natural source. Their structures were elucidated by spectroscopic analysis.     

New Secondary Metabolites from Asphodelus tenuifolius

Asphorins A and B ( 1 and 2 , resp.), two new triterpene glycosides, have been isolated along with a new chromone, 3 , from the AcOEt subfraction of the MeOH extract of the whole plant of Asphodelus tenuifolius. Their structures were elucidated by spectral analysis including 2D‐NMR spectroscopic experiments.     

New Secondary Metabolites from Allium victorialis

Allumines A and B ( 1 and 2 , resp.), two new steroidal alkaloids, and a new cyclopentene derivative, 3 , were isolated from the CHCl₃‐soluble fraction of the whole plant of Allium victorialis. Their structures were elucidated by spectroscopic techniques, including 1D‐ and 2D‐NMR spectroscopy.     

Conversion of Polyethylenes into Fungal Secondary Metabolites

Waste plastics represent major environmental and economic burdens due to their ubiquity, slow breakdown rates, and inadequacy of current recycling routes. Polyethylenes are particularly problematic, because they lack robust recycling approaches despite being the most abundant plastics in use today. We report a novel chemical and biological approach for the rapid conversion of polyethylenes into structurally complex and pharmacologically active compounds. We present conditions for aerobic, catalytic digestion of polyethylenes collected from post-consumer and oceanic waste streams, creating carboxylic diacids that can then be used as a carbon source by the fungus Aspergillus nidulans. As a proof of principle, we have engineered strains of A. nidulans to synthesize the fungal secondary metabolites asperbenzaldehyde, citreoviridin, and mutilin when grown on these digestion products. This hybrid approach considerably expands the range of products to which polyethylenes can be upcycled.     

Secondary Metabolites of Purpureocillium lilacinum

Fungi can synthesize a wealth of secondary metabolites, which are widely used in the exploration of lead compounds of pharmaceutical or agricultural importance. Beauveria, Metarhizium, and Cordyceps are the most extensively studied fungi in which a large number of biologically active metabolites have been identified. However, relatively little attention has been paid to Purpureocillium lilacinum. P. lilacinum are soil-habituated fungi that are widely distributed in nature and are very important biocontrol fungi in agriculture, providing good biological control of plant parasitic nematodes and having a significant effect on Aphidoidea, Tetranychus cinnbarinus, and Aleyrodidae. At the same time, it produces secondary metabolites with various biological activities such as anticancer, antimicrobial, and insecticidal. This review attempts to provide a comprehensive overview of the secondary metabolites of P. lilacinum, with emphasis on the chemical diversity and biological activity of these secondary metabolites and the biosynthetic pathways, and gives new insight into the secondary metabolites of medical and entomogenous fungi, which is expected to provide a reference for the development of medicine and agrochemicals in the future.     

Secondary Metabolites of the Lichen Parmotrema cristiferum

Chemistry of Natural Compounds - A new C41-spiroterpenoid, norreticulatin (1), has been isolated from the thalli of Parmotrema cristiferum together with four known compounds, anadensin (2),...     

Secondary Metabolites from the Fungus Chaetomium brasiliense

Two new depsidones, mollicellins I and J ( 1 and 2 , resp.), and a new chromone, 2‐(hydroxymethyl)‐6‐methylmethyleugenin ( 3 ), along with six known compounds, 4 – 9 , were isolated from the ethyl acetate extract of a solid‐state fermented culture of Chaetomium brasiliense. Their structures were elucidated based on spectroscopic analysis. Mollicellins I and H ( 5 ) exhibited significant growth inhibitory activity against human breast cancer (Bre04), human lung (Lu04), and human neuroma (N04) cell lines with GI₅₀ values between 2.5–8.6 μg/ml.