Prenylated and O-methylflavonoids including one new pterocarpan (1), three new isoflavones (2-4), and nineteen known natural products (5-23) were isolated and identified from the root, stem bark, and leaf extracts of Erythrina schliebenii. The crude extracts and their constituents were evaluated for antitubercular activity against Mycobacterium tuberculosis (H37Rv strain), showing MICs of 32-64 μg mL and 36.9-101.8 μM, respectively. Evaluation of their toxicity against the aggressive human breast cancer cell line MDA-MB-231 indicated EC values of 13.0-290.6 μM (pure compounds) and 38.3 to >100 μg mL (crude extracts).

Coastal forests of Tanzania are endowed with edible wild fruit plant species that can be used as dietary supplements to humans. The antioxidant activities of two common wild fruits Vitex doniana and Saba comorensis from two coastal regions (Tanga and Coastal) were determined using diphenly-1-picrylhydrazyl (DPPH). The antioxidant activities for V. doniana ranged between 71.0 ± 0.4 and 49.11 ± 0.04 in fruit samples from Tanga and 65.6 ± 0.1 and 48.3 ± 0.1 in fruit samples from Coast region. The activity in S. comorensis ranged between 56.28 ± 0.02 and 44.22 ± 0.03 for fruit samples from Coast region and between 61.77 ± 0.00 and 51.8 ± 0.1 for fruit samples from Tanga. However, the differences in antioxidant activity between fruits from the two regions were not significant (P > .05) as they performed on the same latitudinal gradient influenced by the similar coastal habitat conditions. Data indicated a positive correlation between concentration of the fruit extracts and the free radical scavenging capacity where higher antioxidant activity was observed at 1000 µg/ml fruit extract concentration than in 62.5 µg/ml. The regression analysis indicated significant influence of the wild fruit extracts on antioxidant activity in fruit samples from Tanga than it was in fruit samples from Coast regions. The considerable antioxidant activity depicted by the fruits of both V. doniana and S. comorensis indicated their neutraceutical potential as natural antioxidants.

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Phytochemical investigation of Sanrafaelia ruffonammari Verd and Ophrypetalum odoratum Diels that belongs to the rare genera confined to East African coastal forests led to the isolation of enantiomeric styrylpyrone dimer, (±)-5-methoxy-7-phenyl-[4-methoxy-2-pyronyl]-1-(E)-styryl-2-oxabicyclo-[4.2.0]-octa-4-en-3-one (1) alongside (+)-6-styryl-7,8-epoxy-4-methoxypyran-2-one (2) and the enantiomeric (+)- (3) and (−)-6-styryl-7,8-dihydroxy-4-methoxypyran-2-ones (4). Their structures were established by means of spectroscopic methods. In this paper we reveal for the first time the occurrence of styrylpyrones in East African biodiversity. (+)-6-Styryl-7,8-epoxy-4-methoxypyran-2-one (2) and the dihydroxystyrylpyrone enantiomer (3) showed in vitro antifungal activity against Candida albicans at a concentration of 24.4 and 26.2 µM with zones of inhibition of 17 and 9 mm, respectively. Compound 2 exhibited strong activity in the brine shrimp test with LC50 = 1.7 µg/mL. Their high cytotoxic and antifungal activities render them candidates for further scientific attention for drug development programs against cancer and microbial infections.

Characterisation of a novel discolornolide (1) isolated from a first time investigation of Monanthotaxis discolor is described. Other 6 known compounds, karatavin (2), Nacetylanonaine (3), quercetin-3-O--arabinose (4), stigmasterol (5 ), a mixture of stigmasterol and -sitosterol (6) and octahydro-5-isopropyl-3-methyl-2-methyleneazulene-8,8-diol (7) isolated are also reported. The structures were established by spectroscopic methods.Citotoxicities and antimicrobial activities of the compounds and crude extracts are also reported whereby compound 1 showed in vitro antifungal activity against Candida albicans and Aspergilus niger at concentrations of 0.13 and 0.17 mg/ml with zones of inhibitions of 7.0 and 5.5 mm respectively. The compound also showed cyitotoxic activity in the brine shrimp test with LC 50 of 5.88 g/ml. Also compound 4 exhibited antibacterial activity against E. coli and S.aureus. The compound also exhibited cytotoxic activities in the brine shrimp test with LC 50 of 24.73 g/mL. The crude extracts exhibited varying citotoxic and in vitro antimicrobial activities.