Anti-inflammatory and Antiphytopathogenic Fungal Activity of 2,3-seco-Tirucallane Triterpenoids Meliadubins A and B from Melia dubia Cav. Barks with ChemGPS-NP and In Silico Prediction.

Two new rearranged 2,3-seco-tirucallane triterpenoids, meliadubins A (1) and B (2), along with four known compounds, 3-6, were isolated from the barks of Melia dubia Cav. Compound 2 exhibited a significant inflammatory inhibition effect toward superoxide anion generation in human neutrophils (EC50 at 5.54 ± 0.36 µM). It bound to active sites of a human inducible nitric oxide synthase (3E7G) through interactions with the residues of GLU377 and PRO350, which may benefit in reducing the neutrophilic inflammation effect. The ChemGPS-NP interpretation combined with bioactivity assay and in silico prediction results suggested 2 to be an agent for targeting iNOS with different mechanisms as compared to a selected set of current approved drugs. Moreover, compounds 1 and 2 showed remarkable inhibition against the rice pathogenic fungus Magnaporthe oryzae in a dose-dependent manner with IC50 values of 137.20 ± 9.55 and 182.50 ± 18.27 µM, respectively. Both 1 and 2 displayed interactions with the residue of TYR223, a key active site of trihydroxynaphthalene reductase (1YBV). The interpretation of 1 and 2 in the ChemGPS-NP physical-chemical property space indicated that both compounds are quite different compared to all members of a selected set of reference compounds. In light of demonstrated biological activity and in silico prediction experiments, both compounds possibly exhibited activity against phytopathogenic fungi via a novel mode of action.

New cycloartane coronalyl acetate and other terpenoids with anti-inflammatory activity from the leaves of Vietnamese Gardenia philastrei.

Phytochemical study on the methanolic extract of the leaves of Vietnamese plant Gardenia philastrei Pierre ex Pit. has led to the isolation of a new cycloartane coronalyl acetate (1) together with six known ones, coronlolide methyl ester (2), sootepin D (3), coronalolide (4), coronalolic acid (5), sootepin G (6) and 23-deoxojessic acid (7). Their structures were elucidated by a combination of 2 D NMR and HR-ESI-MS spectroscopies. These compounds (1-7) were tested for their anti-inflammatory activity. The result showed that six compounds (1-6) inhibit LPS-induced nitric oxide production in RAW264.7 macrophages with their IC50 values ranging from 3.76 - 75.47 µg/mL. This is the first report on the chemical constituents and anti-inflammatory activity of the G. philastrei.

Myobontioids A-D and antifungal metabolites from the leaves of Myoporum bontioides A. Gray.

A new sesquiterpene glucoside (1), two new norsesquiterpenes (2, 3), and a new homomonoterpene (4), named myobontioids A-D respectively, along with twelve known flavonoids and lignans (5-16) were isolated from Myoporum bontioides A. Gray. Flavanones 5-11 specifically inhibited Phytophthora capsici and Magnaoeporthe grisea at the concentrations of 125, 250 and 500 µg.mL-1. Notably, the new compound 4 possessed a strong activity against Phytophthora capsici with IC50 below 63.5 µg.mL-1 and 90.4% inhibition at 125 µg.mL-1.