Exploring the Impact of Multi-Component Extracts from Loquat Leaves on Different Disorders

OBJECTIVE To extract polysaccharides， flavonoids and triterpene acids from Loquat leaves and evaluate their anti-inflammatory， antioxidant and anti-tumor activities， respectively. METHODS The polysaccharides were prepared by water extraction and ethanol precipitation. The supernatant after ethanol precipitation was used for the enrichment of flavonoids， and residues after water extraction were collected to extract triterpene acids with 90% ethanol reflux extraction. The effect of Loquat leaf polysaccharides on the expression of PAI-1 in TGF-β1-treated murine mesangial cells was detected by Western blot. The antioxidant activity of flavonoids was evaluated by ABTS radical scavenging assay. The effect of triterpene acids on the proliferation of myeloma cell line (ARP1) was examined by MTT assay and the weight of subcutaneous mouse tumors. RESULTS The results showed that the contents of polysaccharides， flavonoids and triterpene acids were 19.53， 48.70， 7.86 g/kg. The polysaccharides could inhibit the expression of PAI-1 in TGF-β1-treated murine mesangial cells. The flavonoids showed an antioxidant activity at the concentration of 75-150 μg/mL. The IC₅₀ value of total triterpene acids on ARP1 cells was 11.57 μg/mL， and it could inhibit the growth of subcutaneous tumors in mice. CONCLUSION Polysaccharides have therapeutic effects on nephritis. Flavonoids and triterpene acids possess anti-oxidation and anti-tumor effects， respectively. Our findings provide supporting evidence for further utilization of Loquat leaves.