Antioxidant and cytotoxicity activities of δ-tocotrienol from the seeds of Allophylus africanus.

Chemical investigation of Allophylus africanus P. Beauv fruits led to the isolation of a new δ-tocotrienol, 3α-hydroxy-δ-tocotrienol (1) together with eight known compounds (2-9). Compound (1) was allylated (1a) and prenylated (1 b and 1c) to give three new semi-synthesized derivatives which were fully characterized as: 6-O-allyl-3α-hydroxy-δ-tocotrienol (1a), 6-O-prenyl-3α-hydroxy-δ-tocotrienol (1 b) and 6-O,5-C-diprenyl-3α-hydroxy-δ-tocotrienol (1c). The structures of compounds were established using comprehensive spectroscopic analysis including UV, MS, 1 D NMR, 2 D NMR and by comparison with the corresponding literature data. Compound (1) and its semi-synthetic derivatives (1a-c) were tested for their antioxydant activity using DPPH radical scavenging assay and also for their cytotoxicity using human cervix carcinoma KB-3-1 cell lines. The results showed that compound (1) exhibited antioxidant activity with an IC50 value of 0.25 µM compared to the reference control trolox (26 µM); and good cytotoxic activity with IC50 values of 97 µM compared to the reference (+)-griseofulvin (IC50 between17-21 µM).

Phytochemical, antibacterial, antioxidant and cytoxicity investigation of Tarenna grandiflora.

The phytochemical investigation of Tarenna grandiflora led to the isolation of 18 known compounds of which were four flavones, three anthraquinones, one phenyl propanoic derivative, five triterpenoids, four steroids and a mixture of glucose. Luteolin (1) and soranjidiol (6) were allylated and/or prenylated to give four new semisynthesized derivatives which were fully characterized as 7,3',4'-O-triallylluteolin (1a), luteolin-7,3',4'-O-triprenyls (1b), luteolin-5,7,3',4'-O-tetraprenyls (1c) and 6-O-allylsoranjidiol (6a). Their structures were established using spectroscopic analysis including 1D, 2D NMR and MS data. The cytotoxic, antioxidant and antimicrobial activities of extracts, fractions, isolated compounds and semi-synthesized derivatives were evaluated. The petroleum ether and EtOAc extracts exhibited good cytotoxic potency on KB-3-1 cell line with IC50 of >0.1 and 0.025 mg/mL respectively, while compounds 1b and 11 were the most active (IC50 > 0.0001 M). Compounds 1 and 3 showed the best antioxidant activities (45.5 and 55.8 µM); while compounds 9 and 12 showed the best antibacterial activities with MICs values ranges from 8.55 to 132 µM.