Chemical Composition and Antimicrobial Activity of a New Chemotype of Hyptis suaveolens (Poit) from Nigeria

Abstract: Hyptis suaveolens is one of the aromatic plants credited for substantial medicinal values in the tropics with three chemotypes previously reported in Nigeria. This study provided biological and chemical evidence for a new chemotype of Hyptis suaveolens in Lagos. Hydrodistillation of the dried leaves of the plant produced volatile oil with a yield of 0.31% and subsequent analyses by GC-MS identified 28 volatile compounds that accounted for 99.1% of the total oil composition. Although the oil was monoterpenoid dominated and has comparable levels of sabinene (25.8 vs. 13.2-30.1%), a-thujene (1.1 vs. 0.9-1.2%), and 4-terpineol (8.4-9.8 vs. 11.4%), it elicited a moderate level of "-pinene (4.7 vs. 1.8-13.6), higher levels of $-pinene (9.7 vs. 0-4.4%), limonene (2.3 vs. 0-0.8%), 1,8-cineole (4.8 vs. 0-1.2%), (-terpinene (9.3 vs. 1.6-4.2%) and terpinolene (8.4 vs. 5.6-6.3) and the presence of new compounds: aromadendrene (0.3%), camphor (0.3%), germacrene B (0.4%) and himachalol (0.1%) when compared with the previous chemotypes. In vitro, the oil was found by agar diffusion assay to elicit antibacterial activity against E. coli ATCC25922, and S. aureus ATCC25923 and antifungal activity with C. albicans showing higher sensitivity (MFC = 53.3 :L/mL) and Aspergillus niger and Trichophyton rubrum displaying moderate to low sensitivity. Biological effect of the oil at sub-MIC on E. coli ATCC25922 was characterized by dose-dependent loss of outer membrane proteins. These findings provide evidence for a new chemotype of Hyptis suaveolens in Nigeria