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Biological activity of luteolin glycosides and tricin from Sasa senanensis Rehder.

BACKGROUND
In contrast to the several reports of alkaline extracts (Sasa-health, SE), no study of flavonoids from the leaves of S. senanensis has been reported. Four flavonoids were isolated from this plant species and their biological activities were investigated.


MATERIALS AND METHODS
Luteolin 6-C-β-D-glucoside [1], luteolin 7-O-β-D-glucoside [2], luteolin 6-C-α-L-arabinoside [3] and tricin [4] were extracted from the leaf of S. senanensis with methanol, partitioned with ethyl acetate, separated by Sephadex LH-20 and purified by high-performance liquid chromatography (HPLC). The structure was determined by ultraviolet (UV) spectra, high-resolution mass spectra (HR-MS) and nuclear magnetic resonance (NMR).


RESULTS
The luteolin glycosides, 1-3 showed no cytotoxicity against the human normal oral cells and oral squamous cell carcinoma cell lines used up to 0.8 mg/ml, whereas 4 was highly cytotoxic. The luteolin glycosides 1-3 protected the cells from UV induced cytotoxicity, more efficiently than 4. The anti-HIV activity of 4 (Selectivity index, SI=27) was much higher than that of the luteolin glycosides (SI=2-7), but lower than that of SE (SI=40). The scavenging activity of 1-3 against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide anion radicals was comparable with that of quercetin and, much higher than that of 4.


CONCLUSION
The luteolin glycosides from S.senanensis show several new biological properties distinct from tricin and the anti-UV activity of the luteolin glycosides may be derived from their radical scavenging activity.