Antioxidant Activity, Total Phenolic and Flavonoid Contents of Some Folkloric Medicinal Vegetables in Ifugao, Philippines

MARIE ANN CULHI-GALVEZ
Ifugao State University
Email: mculhi@yahoo.com
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ABSTRACT
Antioxidants are substances which have the ability to remove the potentially
damaging oxidizing agents in a living organism. Many phytochemicals present in
plants are able to reduce or prevent the oxidative damage to the human cells which
can cause even cancer in humans. This study identified the phytochemicals present,
antioxidant activity, and the total phenolic and flavonoid contents in the three
folkloric medicinal vegetables grown in Ifugao, Cordillera Administrative Region,
Philippines namely: Diplazium esculentum (Retz)(Apaku), Physalis angulata L.
(Gupa-gupa), Solanum nigrum L. (Amti). Phytochemical screening followed
standard methods, antioxidant activity was measured using 2,2-diphenyl-1-
picrylhydrazyl (DPPH) free radical scavenging assay, total phenolic content was
identified using the Folin-Ciocalteu method and the total flavonoid content followed
the Aluminum chloride colorimetric method. Results revealed that the following
phytochemicals like alkaloids, carbohydrates, saponins, phenolic contents, tannins,
and flavonoids were present in the vegetables. All the vegetables have higher
antioxidant activity than ascorbic acid (control) at 62.5 µg/mL. The highest total
phenolic content was measured in Diplazium esculentum (Retz.) (6.077±0.4587 μg/
mL) followed by Solanum nigrum L. (4.026±0.2526 μg/mL) and the lowest was
observed in Physalis angulata L. (0.7216±0.1010 μg/mL). Solanum nigrum L.
(8.843±0.2585 mg QE/g sample) has the highest total flavonoid content followed by
Diplazium esculentum (Retz.) (8.399±0.1173 mg QE/g sample) and the lowest was
obtained in Physalis angulata L. (7.214±0.01186 mg QE/g sample). The antioxidant
activity of the plant extracts are attributed to their total phenolic and flavonoid
contents. Further investigation is required to isolate and characterize the potential
antioxidant compounds from these vegetables and develop their applications for food
and pharmaceutical industries.

Keywords: free radical, DPPH assay, phytochemicals, scavenging activity