The anti-venom potential of Andrographis paniculata (Burm.f.) Nees roots and its constituent skullcapflavone I

The anti-venom activity of Andrographis paniculata (Burm.f.) Nees roots (APR) dichloromethane crude extractsand a promising APR constituent, skullcapflavone I (SKI) was investigated by monitoring the inhibition of secretoryphospholipase A2 (sPLA2) of Naja philippinensis Taylor venom (NPV) crystallized samples. Gas chromatographymass spectrometry was used for the characterization of extracts, while molecular docking was utilized to understandanti-venom properties. Chromatographic analyses primarily revealed the presence of methoxylated flavones. NPV wasfound to have sPLA2 activity (0.0796 ± 0.0018 μmol/minutes/ml) that has been attributed to the poisonous effects.SKI (IC50: 51.1 ± 3.5 μg/ml), isolated from APR showed strong inhibitory effect on phospholipase activity comparedwith dichloromethane extracts of APR (IC50: 192.7 ± 10.9 μg/ml) indicating that SKI was the cause of the bioactivityin APR. Molecular docking simulations showed corresponding results with highly negative binding energies (−6.59 to−8.72 kcal/mol) predicted for the binding of SKI to PLA2 proteins. An important trend found was the presence of freebound Ca2+ lowered binding energies signifying that Ca2+ a has role in the binding of the SKI to PLA2 proteins. Theanti-venom property of APR and the pure compound SKI, upon further studies, could be the first line of defense in themedical protocol of snake venom neutralization.

The anti-venom potential of Andrographis paniculata (Burm.f.) Nees roots and its constituent skullcapflavone I

The anti-venom activity of Andrographis paniculata (Burm.f.) Nees roots (APR) dichloromethane crude extractsand a promising APR constituent, skullcapflavone I (SKI) was investigated by monitoring the inhibition of secretoryphospholipase A2 (sPLA2) of Naja philippinensis Taylor venom (NPV) crystallized samples. Gas chromatographymass spectrometry was used for the characterization of extracts, while molecular docking was utilized to understandanti-venom properties. Chromatographic analyses primarily revealed the presence of methoxylated flavones. NPV wasfound to have sPLA2 activity (0.0796 ± 0.0018 μmol/minutes/ml) that has been attributed to the poisonous effects.SKI (IC50: 51.1 ± 3.5 μg/ml), isolated from APR showed strong inhibitory effect on phospholipase activity comparedwith dichloromethane extracts of APR (IC50: 192.7 ± 10.9 μg/ml) indicating that SKI was the cause of the bioactivityin APR. Molecular docking simulations showed corresponding results with highly negative binding energies (−6.59 to−8.72 kcal/mol) predicted for the binding of SKI to PLA2 proteins. An important trend found was the presence of freebound Ca2+ lowered binding energies signifying that Ca2+ a has role in the binding of the SKI to PLA2 proteins. Theanti-venom property of APR and the pure compound SKI, upon further studies, could be the first line of defense in themedical protocol of snake venom neutralization.

Chemical constituents of Cinnamomum cebuense / 中国天然药物

AIM@#To investigate the chemical constituents of Cinnamomum cebuense, an endemic and critically endangered tree found only in Cebu, Philippines.@*METHODS@#The compounds were isolated by silica gel chromatography. The structures of the isolates were elucidated by NMR spectroscopy.@*RESULTS@#The dichloromethane (DCM) extract of the bark of C. cebuense afforded a new monoterpene natural product 1 and a new sesquiterpene 2, along with the known compounds, 4-hydroxy-3-methoxycinnamaldehyde (3), 4-allyl-2-methoxyphenol (4), α-terpineol (5) and humulene (6). The DCM extract of the leaves of C. cebuense yielded 6, β-caryophyllene (7), squalene (8), and a mixture of α-amyrin (9), β-amyrin (10) and bauerenol (11). The structures of 1-7 were elucidated by extensive 1D and 2D NMR spectroscopy, while the structures of 8-11 were identified by comparison of their (13)C NMR data with those reported in the literature.@*CONCLUSION@#The bark of C. cebuense afforded monoterpenes, sesquiterpenes and phenolics, while the leaves yielded sesquiterpenes and triterpenes.

Angio-suppressive triterpenoids from Ardisia cf. elliptica (subgenus Tinus) on duck (Anas platyrynchos L.) chorioallantoic membrane / 中国天然药物

The dichloromethane extract of the air-dried leaves of Ardisia cf. elliptica (subgenus Tinus) afforded a mixture of bauerenol (1a), α-amyrin (1b) and β-amyrin (1c). Their structures were identified by NMR spectroscopy. Mixtures of the triterpenes (1a-1c) at ratios of 2 : 2 : 1, 2 : 2 : 3 and 1 : 1 : 1 were tested for their angio-suppressive effects on duck chorioallantoic membrane (CAM). All three ratios were found to be effective in restricting inter-capillary length, while 1a-1c (2 : 2 : 1) was most effective in reducing branch point density with 100% CAM viability and embryo survivability, suggesting a high impact angio-suppressive potential of 1a-1c (2 : 2 : 1).

Triterpenes from Euphorbia hirta and their cytotoxicity / 中国天然药物

AIM@#To investigate the chemical constituents of the stems, leaves and roots of Euphorbia hirta, and to test for the cytotoxic and antimicrobial potentials of the major constituents of the plant.@*METHODS@#The compounds were isolated by silica gel chromatography and their structures were elucidated by NMR spectroscopy. The cytotoxicity tests were conducted using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, while the antimicrobial tests employed the agar well method.@*RESULTS@#The air-dried stems of E. hirta afforded taraxerone 1, a mixture of 25-hydroperoxycycloart-23-en-3β-ol (2a) and 24-hydroperoxycycloart-25-en-3β-ol (2b) (sample 2) in a 2 : 1 ratio, and another mixture of cycloartenol (3a), lupeol (3b), α-amyrin (3c) and β-amyrin (3d) (sample 3) in a 0.5 : 4 : 1 : 1 ratio. The air-dried leaves of E. hirta yielded sample 2 in a 3 : 2 ratio, sample 3 in a 2 : 3 : 1 : 1 ratio, phytol and phytyl fatty acid ester, while the roots afforded sample 2 in a 2 : 1 ratio, sample 3 in a 2 : 1 : 1 : 1 ratio, a mixture of cycloartenyl fatty acid ester 4a, lupeol fatty acid ester 4b, α-amyrin fatty acid ester 4c and β-amyrin fatty acid ester 4d (sample 4) in a 3 : 2 : 1 : 1 ratio, linoleic acid, β-sitosterol and squalene. Compound 1 from the stems, sample 2 from the leaves, and sample 3 from the stems were assessed for cytotoxicity against a human cancer cell line, colon carcinoma (HCT 116). Sample 2 showed good activity with an IC50 value of 4.8 μg·mL(-1), while 1 and sample 3 were inactive against HCT 116. Sample 2 was further tested for cytotoxicity against non-small cell lung adenocarcinoma (A549). It showed good activity against this cell line with an IC50 value of 4.5 μg·mL(-1). Antimicrobial assays were conducted on 1 and sample 2. Results of the study indicated that 1 was active against the bacteria: Pseudomonas aeruginosa and Staphylococcus aureus, but was inactive against Escherichia coli and Bacillus subtilis. Sample 2 was active against the bacteria: Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli and fungi: Candida albicans and Trichophyton mentagrophytes. It was inactive against Bacillus subtilis and Aspergillus niger.@*CONCLUSIONS@#The triterpenes: 2a, 2b, 3a, 3b, 3c and 3d were obtained from the stems, roots and leaves of E. hirta. Taraxerol (1) was only isolated from the stems, the leaves yielded phytol and phytyl fatty acid esters, while the roots afforded 4a-4d, linoleic acid, β-sitosterol, and squalene. Triterpene 1 and sample 2 were found to exhibit antimicrobial activities. Thus, these compounds are some of the active principles of E. hirta which is used in wound healing and the treatment of boils. The cytotoxic properties of sample 2 imply that triterpenes 2a and 2b contribute to the anticancer activity of E. hirta.