The Antifungal Activities Of Aromatic Plants' Essential Oils And The Constituents Against Colletotrichum Orbiculare

Nowadays, Colletotrichum orbiculare (Berk. & Ment.) has been recognized as one of the most frequently happened and economically damaged plant pathogens in the world, especially in the humid crop areas. Historically, the conventional inhibitory methods mainly relying on pesticides fail to satisfy the researchers by their relatively poor antifungal activities, cost-consuming nature and incredibly high left-over, which urges researchers to find a brand new, more effective way to control the disease. Aromatic plants essential oils have proven antifungal activities, more or less, on a large scale of pathogens, and are actually the hot spots in the pesticide research.The experiment distilled the essential oils from over 10 kinds of aromatic plants, which were growing in the Chongming Island, and tested their antifungal activities by investigating the effects they put on mycelia growth. Rosemary (Rosmarinus officinalis L.), Lavender (Lavandula angustifolia) and Peppermint (Mentha piperita) demonstrated very strong antifungal activities and were put to the next level rectifying after detailed GC-MS analysis. Rosemary was divided into 2 major constituents (α-Pinene and 1, 8-Cineole), 1 minor constituents (Verbenone), and the mixture of other minor constituents and track constituents; Lavender was divided into 1 major constituent (Linalool), and the mixture of other minor constituents and track constituents; Peppermint was also divided into 2 major constituents (Menthal, Menthone), 2 minor constituents (1, 8-Cineole, Isomenthone), and the mixture of other minor constituents and track constituents. Further study ensured the antifungal activities of constituents listed and demonstrated that the synergisms and counteractions existed amongst all the 3 aromatic plants essential oils.The results are shown as follow:1. The three aromatic plants'essential oils all demonstrate considerable inhibitory abilities against Colletotrichum orbiculare (Berk.&Ment.). Lavender essential oil shows the strongest antifungal activity, followed by Peppermint essential oil and Rosemary essential oil.2. The sequence of the antifungal activities of major comstituents and minor constituents recitified from the 2 essential oils listed are: Menthol > Linalool > 1, 8-Cineole > Isomenthone >α-Pinene.Based on the in-depth research of distilled essential oils, 3 aromatic plants'essential oils have been selected and put into the next level of test, including GC-MS and rectifying. The constituents separated by rectifying were later put into the screening test as well. The study aims to further the foundation of fully utilizing aromatic plants essential oils and the constituents on initiating new biological pesticide.