Comparative Analysis of Chemical Constituents and Antioxidant Properties of Fresh and Air-Dried Leaves’ Essential Oils of Rauwolfia vomitoria (Afzel)

To enhance the essential oil information of Rauwolfia vomitoria (Afzel), we compared the essential oil constituents and antioxidant activities of the fresh and air-dried leaves. The leaves are traditionally used to treat infections, fevers, snake bites, rheumatism, and to calm people with anxiety or epilepsy. The GC, GC/MS results showed the fresh leaves’ oil contained thirty-three compounds while the air-dried leaves' oil contained twenty-eight. The fresh and air-dried leaves had β-citral (31.32% and 33.68%), α-citral (26.04% and 38.09%), Isogeranial (9.99% and 1.33%), and isoneral (4.22% and 1.00%), respectively. Neric acid (2.27%), geranic acid (2.52%), geranyl acetate (2.33%), palmitic acid (2.17%), and organosilicon compounds (4.94%) were present in either of the oils. At 400 µg/mL, the fresh and air-dried leaves' oils gave 30.55% and 25.34% mild antioxidant activity compared to ascorbic acid’s 96.50%. The natural antibiotic agents (Citral and its stereoisomers) present in the oils could contribute to the traditional use of the plant in treating various diseases, particularly those that are microbial. The mild antioxidant activity observed is important in health issues because the risk of adverse reactions or interactions is thus reduced compared to when stronger antioxidants are used. This work has improved the scarce information on the plant’s essential oil constituents and activities.