Chemical constituents of the Annona glabra fruit and their cytotoxic activity

Context: Traditional Chinese medicines have attracted increasing interest as potential sources of novel drugs with a wide range of biological and pharmacological activities. Annona glabra Linn (Annonaceae) is used in traditional medicine as an anticancer drug. Phytochemical investigation of this plant led to the isolation of acetogenins, ent-kauranes, peptides, and alkaloids. In addition, compounds exhibited anticancer, anti-HIV-reserve, and antimalaria. Objective: Isolation, structure determination, and cytotoxic activity evaluation of compounds from the methanol extract from A. glabra fruits. Materials and methods: Using chromatographic methods to isolate compounds from the A. glabra methanol extract. The cytotoxic activity of compounds was evaluated by a 3-[4,5- dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. In addition, compounds which showed significant cytotoxic activity were chosen for further study apoptosis characteristics. Results: One new, (2E,4E,1'R,3'S,5'R,6'S)-dihydrophaseic acid 1,3'-di-O-β-D-glucopyranoside, and eight known compounds, (2E,4E,1'R,3'S,5'R,6'S)-dihydrophaseic acid 3'-O-β-D-glucopyranoside (2), icariside D₂ (3), icariside D₂ 6'-O-β-D-xylopyranoside (4), 3,4-dimethoxyphenyl O-β-Dglucopyranoside (5), 3,4-dihydroxybenzoic acid (6), blumenol A (7), cucumegastigmane I (8), and icariside B₁ (9), were isolated from the fruits of A. glabra. Icariside D₂ (3) was found to show significant cytotoxic activity on the HL-60 cell line with the IC₅₀ value of 9.0 ± 1.0 μM and did not show cytotoxic activity on the Hel-299 normal cell line. The further test indicated that compound 3 induced apoptosis via alteration of expression of apoptosis-related proteins and decreased phosphorylation of AKT in HL-60 cells. Discussion and conclusion: The results suggested that the constituents from A. glabra may contain effective compounds which can be used as anticancer agents.