Research articles
ScienceAsia 52 (2026):ID 2026042 1-7 |doi:
10.2306/scienceasia1513-1874..042
Comparative phytochemicals and biological activities of
ethanolic extracts of Clinacanthus nutans leaves and
validation of HPLC method for vitexin
Supharat Duanyaia, Boonlong Sribuaa, Atchara Kaewnoib, Omboon Vallisutaa, Petnumpung Rodpoa,*,
Arwut Hongsiria, Jantana Yahuafaic, Tida Amond
ABSTRACT: Phaya Yo (Clinacanthus nutans) leaves have been traditionally used in Thailand to treat insect stings
and herpes virus infections. Their efficacy is recognized, leading to the inclusion of a 95% ethanolic extract in the
Thai National Essential Medicine List. The plant?s key active compounds are apigenin-C-glycoside flavones, including
vitexin, iso-vitexin, orientin, and schaftoside, though their levels vary due to environmental factors and extraction
methods. This study examined different drying methods?oven drying, parabolic dome drying, and sun drying?
followed by maceration using 95%, 70%, and 50% hydro-alcoholic solvents. Results showed that oven drying yielded
the highest antioxidant activity, total phenolic content (TPC), and total flavonoid content (TFC). The 95% ethanolic
extract outperformed the others in antioxidant activity, TPC, TFC, and inhibition of nitric oxide (NO) production in
LPS-stimulated RAW 264.7 cells. HPLC analysis confirmed the presence of vitexin but not schaftoside, with the highest
vitexin content (308.67?1.36 ?g/g dry weight) found in the 95% ethanolic extract. These findings support the use of
oven-dried C. nutans leaves extracted with 95% ethanol for optimal bioactivity. This study also provides an improved
HPLC system for analyzing apigenin-C-glycoside flavones in C. nutans leaf extract.
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| a |
Department of Thai Traditional Medicine, Bansomdejchaopraya Rajabhat University, Bangkok 10600 Thailand |
| b |
Graduate School, Bansomdejchaopraya Rajabhat University, Bangkok 10600 Thailand |
| c |
Clinical Research and Innovation Section, Division of Research and Technology Assessment, National Cancer
Institute, Bangkok 10400 Thailand |
| d |
Chemistry Program, Faculty of Science and Technology, Bansomdejchaopraya Rajabhat University,
Bangkok 10600 Thailand |
* Corresponding author, E-mail: petnumpung.ro@bsru.ac.th
Received 6 Mar 2025, Accepted 30 Apr 2026
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