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SummaryThe methanolic extract of seeds of the tropical fruit camu-camu was screened for its anti-inflammatory activity in carrageenan-induced paw edema model mice. The extract significantly suppressed both the formation of edema in mice by oral administration and the release of nitric oxide from macrophage-derived RAW 264.7 cells in vitro. Based on the results of a spectroscopic analysis, the active compound was identified by in vivo bioassay-guided fractionation to be 3 ␤ -hydroxy-lup-20(29)-en-28-oic acid, betulinic acid, known as an anti-inflammatory triterpenoid. These findings suggest that camu-camu seed extract is a potentially useful material as a source of betulinic acid and as a functional food for prevention of immune-related diseases.

The methanol extract of kiwifruit leaf suppressed the postprandial blood glucose level after an oral administration of soluble starch or sucrose in mice. The mechanism of action is proposed to be due to the alpha-amylase-inhibiting activity in the 90% aqueous methanol fraction and alpha-glucosidase-inhibiting activity in the n-buthanol fraction, based on the results of in vitro experiments.

Peach leaf extract has anti-hyperglycemic effects on the postprandial blood glucose level in glucoseloaded mice. In our previous study, the mechanism of action was considered to be the inhibition of glucose absorption in the small intestine. To elucidate the active principle in peach leaf, purification of the active compound and a structure determination were performed. With the use of bioassay-guided fractionation using glucose-loaded mice, the acetylated kaempferol glycoside multiflorin A (MFA), a potent inhibitor of glucose absorption from the intestine, was isolated from the MeOH extract of leaf of the edible peach Prunus persica. The structure was identified by HPLC using thiazolizine derivatives and by an analysis of its spectral data. The inhibitory effect of MFA against glucose absorption was demonstrated in the dose dependent manner in mice. However, as the deacetylated analog of MFA, multiflorin B did not show the activity at the in vivo, the activity of MFA was suggested to depend on the acetyl group on the sugar moiety. This is the first report of anti-hyperglycemic activity of MFA in peach leaf extract. MFA may be useful in functional foods or medicines for preventing the postprandial absorption of glucose in hyperglycemia.

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