Abstract:

Objective: To explore the hypoglycemic constituents of ethyl acetate extract of Psidium guajava Linn. leaves.
Methods: The constituents were separated and purified by silica gel and Sephadex LH-20 column chromatography. The
structures were identified on the basis of their physicochemical properties and spectral data. The hypoglycemic activities
of five major flavonoid glycosides were tested in the hypoglycemic model of isolated rat adipocytes. Results: Fourteen
compounds were isolated and identified as hyperoside compound (1), isoquercitrin compound (2), quercetin-3-O-β-Dxylpyranoside
compound (3), avicularin compound (4), guaijaverin compound (5), quercetin 3-O-α-arabinopyranoside-2’’-
gallate compound (6), quercetin compound (7), ethyl gallate compound (8), oleanolic acid compound (9), β-sitosterol compound
(10), isocaryolan-9-one compound (11), (-)-epiglobulol compound (12), t-cadinol compound (13), and muurola-4,10 (14)-dien-
1-ol compound (14), respectively. At the same concentration of 40 μmol/L, avicularin and guaijaverin showed the most
potent hypoglycemic activity among five major flavonoid glycosides with the glucose uptake value at (1.81 ± 0.029) and
(1.74 ± 0.076) mmol/L respectively. Conclusions: Compounds 6, 8, 11 through 14 were isolated from this plant for the first
time and compound 11 was a new natural compound. Avicularin (4) and guaijaverin (5) may be the most potent hypoglycemic
compounds of guava leaves.

Key words: Psidium guajava Linn., flavanoids, sesquiterpenes, isocaryolan-9-one, chemical constituents, hypoglycemic activity