Moreno, Patrick Gabriel G., Clemente, Liezel G., Deguit, Christian Deo T., Diopol, Garry., Gomez, Marineil C., Manalo, Richelle Ann M., Mercado, Van Jerwin P., Valerio, Von Luigi M.

and Heralde, Francisco M., III Department of Biochemistry and Molecular Biology, College of Medicine

University of the Philippines-Manila

Study Background

Ten endemic plants were declared medicinal

by the Philippine Department of Health for

their reported therapeutic applications and

labeled as the “sampung halamang gamot”.

Knowledge on the medicinal uses of these

plants had so far not considered enzyme

inhibitory activities targeted to human salivary

α-amylase. Inhibition of this enzyme may

contribute to the management of diabetes

through modulation of post-prandial blood

glucose levels.

Methodology

Objectives

Many herbal medicines claim their anti-

diabetic capability, but only few have gained

interest because of the lack of scientific basis

on the exact mechanism for lowering blood

glucose levels. This study aims to screen eight

of the ten plants for their potential α-amylase

inhibitory activity, namely, lagundi, ulasimang

bato/pansit-pansitan, bawang, bayabas,

sambong, ampalaya, tsaang gubat and

akapulko.

Results

Figure 1. Alkaloids present in

ampalaya, determined by

HPLC (226 nm).

Figure 2. Flavonoids present

in bawang, determined by

HPLC (340 nm).

Discussion Conclusion

The reduced activity of the ampalaya and bawang extracts (22.56% and

20.75%, respectively) suggest that one possible mechanism by which

these plants reduce blood glucose level is through reduction of α-amylase

activity by delaying glucose absorption and thus, reducing carbohydrate

metabolism. This may be attributed to the secondary metabolites such as

alkaloids, diterpenes, flavonoids and phenols present in the aqueous

fractions of ampalaya and bawang extracts that demonstrated their role as

hypoglycemic agents by regulating the activity and expression of the rate-

limiting enzymes involved in the carbohydrate metabolism.

This study demonstrated the anti-diabetic potential of aqueous fraction of

bawang and ampalaya via reduction of α-amylase activity. Qualitative

phytochemical screening and HPLC analysis showed the presence of

secondary metabolites such as alkaloids, diterpenes, flavonoids and

phenols that may contribute to the modulation of the postprandial blood

glucose. A detailed investigation on the mechanism of α-amylase

inhibition is recommended to ascertain its anti-diabetic potential.

Furthermore, in vivo study is necessary to confirm these results.