Herbal plants can be an alternative source of therapy especially against hypertension, which is a prevalent burden in the Philippines. This study investigates the phytochemical composition and angiotensin-converting enzyme 1 (ACE-1) inhibitory activity of Mayana (Coleus scutellarioides Benth.) leaf extract, a plant ethnobotanically reported to be used for its potential antihypertensive properties and yet still lacking in in-vitro investigations.

Employing a laboratory experimental research design and standard procedures for phytochemical screening and ACE-1 inhibitory assay, the study compares a crude ethanolic dehydrated leaf extract of Mayana with the positive control, Captopril.

Phytochemical screening revealed the presence of flavonoids and phenolic compounds. ACE-1 inhibitory activity of Mayana at 10 μg/mL, 25 μg/mL, 50μg/mL, 100 μg/mL, 500 μg/mL, 1000 μg/mL were 0.00% ± 0.0000, 12.40% ± 2.7094, 18.76% ± 0.7232, 27.31% ± 2.2159, 30.44% ± 1.6022, 40.12% ± 2.4385, respectively. Mayana exhibited an IC50 value of 55.9154 μg/mL compared to Captopril which was 7.7232 μg/mL, indicating potency disparities.

Mayana has been shown to contain flavonoids and phenolic compounds that exhibit preliminary anti- hypertensive potential through the inhibition of ACE-1. However, the bioactivity of Mayana is lower when compared with a positive control. As such, more research is needed. Despite that, this research contributes to our under- standing of Mayana as a medicinal plant and its potential contribution to complementary and alternative healthcare, with implications for patient care, community awareness, farmer livelihood, education, and future research.