Volatile Terpenes from Essential Oils of Selected Medicinal Plants Grown in Vietnam Forest Reserves

Essential oil constituents of six plants were analyzed by gas chromatography–flame ionization detection (GC-FID) and gas chromatography–mass spectrometry (GC-MS). Melodorum vietnamense var. calcareum leaf oil contained β-caryophyllene (16.4%), sabinene (12.7%), and bicyclogermacrene (10.0%); Melodorum indochinense leaf oil contained bicyclogermacrene (17.2%), sabinene (14.6%), and bicycloelemene (10.8%); Meiogyne monogyna leaf and stem oils were characterized by bicyclogermacrene (38.1% and 49.3%, respectively), β-caryophyllene (15.0% and 16.8%, respectively), and linalool (8.0% and 6.6%, respectively); Meiogyne hainanensis leaves oil contained δ-cadinene (36.6%) and linalool (16.9%), while the stem oil was rich in δ-cadinene (49.3%) and spathulenol (16.3%); Xylopia vielana leaf oil contained β-elemene (19.7%), bicyclogermacrene (15.0%), germacrene D (14.9%), and camphene (11.3%); and the leaf oil of Xylopia pierrei contained β-elemene (23.4%), bicycloelemene (13.9%), β-caryophyllene (11.2%), bicyclogermacrene (10.8%), and germacrene D (10.2%).