Solvent Optimization of Pitang Leaves (Gynochthodes sublanceolata Miq.) Extraction for Bacterial Growth Inhibition

Abstract

Nang dam or Pitang (Gynochthodes sublanceolata Miq.) is a medicinal plant, found in southern Thailand. The leaves are mostly used as a natural food coloring agent and the studies on the pharmacological properties of this plant are needed. The aim of this study was to compare the effectiveness of solvents used for extracting Nang dam leaves and investigate their antibacterial activity. Water, ethanol, acetone, and ethyl acetate were used to extract the leaves. The extraction yield of the crude ranged from 1.14 to 3.2. The highest yield was found in the water-soluble extract (3.2%). However, acetone-soluble extract rendered the highest antibacterial activity using the disc diffusion method, this concluded that acetone was the suitable solvent for extracting Nang dam leaves. The average inhibition zone for Bacillus subtilis ATCC 6051 was 10.00±0.667 mm, and Staphylococcus aureus ATCC 6538P was 6.90±0.875 mm, respectively. Therefore, the acetone extract of Nang dam leaves inhibited Gram-positive bacteria more effective than other solvents. However, its pharmacological properties, such as antioxidant activity and toxicity in living organisms required further studies.