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Three labdane diterpenes, namely labda-8(17),14-diene, 13-epicupressic acid, and 13-Oacetyl- 13-epicupressic acid, were isolated from the resin collected from stem exudates of Araucaria heterophylla Salisb. (Araucariaceae). The isolated compounds were identified using different spectroscopic methods (1H NMR, 13C NMR, HMQC, HMBC and COSY). The resin extract showed antiulcerogenic activity against ethanol-induced stomach ulcers in Sprauge Dawely rats using ranitidine as standard. In addition, the resin and the isolated compounds showed variable cytotoxic activities against breast (MCF7) and colon (HCT116) cancer cell lines.

Four new compounds were isolated from the methanol extract of the aerial parts of Anarrhinum orientale: 6'-O-cinnamoylmussaenosidic acid (1), 6'-O-cinnamoyl-8-O-(6'''-O-cinnamoylglucopyranosyl)mussaenosidic acid (2), (2E,6E)-8-{[(2E,6E)-8-hydroxy-2,6-dimethylocta-2,6-dienoyl]oxy}-2,6-dimethylocta-2,6-dienoic acid (3), and (2E,6E)-8-{[(2E,6E)-8-acetoxy-2,6-dimethylocta-2,6-dienoyl]oxy}-2,6-dimethylocta-2,6-dienoic acid (4). The known 8-O-cinnamoylmussaenosidic acid (5) was also identified. All five compounds were tested for inhibition of the hepatitis C virus (HCV) protease. Compounds 1 and 5 exhibited moderate activity, while 2 and 3 showed weak effects. No inhibitory activity on the human serine protease was observed for any of these compounds, which may infer the selectivity toward the viral protease. A computational docking study of the isolated compounds against HCV protease was used to formulate a hypothetical mechanism for the inhibitory activity of the active compounds on the enzymes tested.

Background:Manilkara zapota (L.) Van Royen is an evergreen tree, native to the tropical Americas and introduced to Egypt as a fruiting tree in 2002. No previous study was reported on the plant cultivated in Egypt.Materials and Methods:In this study, the leaves of the plant cultivated in Egypt were subjected to phytochemical and biological investigations. The lipoidal matter was analyzed by GLC. Five compounds were isolated from the petroleum ether and ethyl acetate fractions of the alcoholic extract of the leaves by chromatographic fractionation on silica gel and sephadex, the structures of these compounds were identified using IR, UV, MS, 1H-NMR and 13C-NMR. The LD50 of the alcoholic and aqueous extracts of the leaves was determined and their antihyperglycemic, hypocholesterolemic and antioxidant activities were tested by enzymatic colorimetric methods using specific kits.Results:Unsaturated fatty acids represent 32.32 % of the total fatty acids, oleic acid (13.95%), linoleidic acid (10.18 %) and linoleic acid (5.96 %) were the major ones. The isolated compounds were identified as lupeol acetate, oleanolic acid, apigenin-7-O-α-L-rhamnoside, myricetin-3-O-α-L-rhamnoside and caffeic acid. This is the first report about isolation of these compounds from Manilkara zapota except myricetin-3-O-α-L-rhamnoside, which was previously isolated from the plant growing abroad. The LD50 recorded 80 g/Kg b. wt. for both the tested extracts, so they could be considered to be safe. They exhibited antihyperglycemic, hypocholesterolemic and antioxidant activities.Conclusion:The observed biological activities were attributed to the different chemical constituents present in the plant mainly its phenolic constituents.

β-amyrin-3-(3’-dimethyl) butyrate, a new natural compound was isolated from the fruits of Manilkara zapota (L.) Van Royen, in addition to lupeol-3-acetate and 4-caffeoylquinic acid (cryptochlorogenic acid). The structures of these compounds were identified using different spectral methods (IR, MS, UV, 1H-NMR, 13C-NMR and 2D-NMR). The alcoholic and aqueous extracts of the unripe fruits, in addition to their aqueous homogenate exhibited antioxidant, antihyperglycemic and hypocholesterolemic activities.