Biological Activities and Crystal Structure Determination of trans, trans-Cyclohexane-1,2,4,5-tetrol Monohydrate from Pseuduvaria phuyensis (R.M.K. Saunders)

Pseuduvaria phuyensis (Annonaceae), was collected from Kanchanaburi Province, western Thailand. The study aimed to evaluate the antibacterial, anti-HIV-1RT, anti-syncytium (MC99+1A2), and cytotoxic potentials of the crude hexane, ethyl-acetate, and methanol extracts of P. phuyensis leaf-twigs and stems, all in comparison with standard drugs. Also, the isolation and characterization of a compound from one of the active extracts as well as its antibacterial and cytotoxicity activities were carried out. The MIC and MBC values of selected bacterial strains ranged from 3.125 – 200 and 6.25 – 200 mg/mL, respectively for all the extracts, while the isolated compound was not active. The anti-HIV-1 RT and the anti-syncytium assay of the hexane and ethyl acetate extracts revealed they were very active, with % inhibitions of 90.50 and 89.36, respectively. The best inhibitory concentration at 50% (IC50) value was 44.33 µM as exhibited by the hexane extract of the stems of the reverse transcriptase assay, while, the best effective concentration at 50% (EC50) value was 10.4 µM (TI>4.83) as displayed by the ethyl acetate extract of the stems. The cytotoxicity study showed that the hexane extract of the stems displayed high cytotoxicity with ED50 value at 13.07 µg/mL against the FaDu cancer cell line, whil that of the isolated compound was not active. The structure of the isolated compound was characterized and elucidated as trans, trans-cyclohexane-1, 2, 4, 5-tetrol monohydrate using spectroscopic technique and X-ray crystallography analysis.