Browsing by Author "Ranasinghe, L.S."

Now showing 1 - 3 of 3

Fungicidal activity of essential oils of Cinnamomum zeylanicum (L.) and Syzygium aromaticum (L.) Merr et L.M.Perry against crown rot and anthracnose pathogens isolated from banana
(Letters in Applied microbiology, 2002) Ranasinghe, L.S.; Jayawardena, B.M.; Abeywickrama, K.P.
Aims: To develop a post-harvest treatment system against post-harvest fungal pathogens of banana using natural products. Methods and Results:Colletotrichum musae was isolated and identified as the causative agent responsible for anthracnose peel blemishes while three fungi, namely Lasiodiplodia theobromae, C. musae and Fusarium proliferatum, were identified as causative agents responsible for crown rot. During the liquid bioassay, cinnamon [Cinnamomum zeylanicum (L.)] leaf, bark and clove [Syzygium aromaticum (L.)] oils were tested against the anthracnose and crown rot pathogens. The test oils were fungistatic and fungicidal against the test pathogens within a range of 0�03?0�11% (v/v). Conclusions:?Cinnamon and clove essential oils could be used as antifungal agents to manage post harvest fungal diseases of banana. Significance and Impact of the Study: Cinnamon and clove essential oil could be used as alternative post-harvest treatments on banana. Banana treated with essential oil is chemically safe and acceptable to consumers. Benomyl (Benlate), which is currently used to manage fungal pathogens, can cause adverse health effects and could be replaced with volatile essential oils.
Polyphenol oxidase inhibitory activity of essential oils of Cymbopogon nardus and Cymbopogon citratus
(Journal of Tropical Medicinal plants, 2003) Ranasinghe, L.S.; Jayawardena, B.M.; Abeywickrama, K.P.
Polyphenol oxidase (tyrosinase) (EC 1.14 18.1) is responsible for the hyperpigmentation in humans, insect molting process and browning reactions of plants. There is interest to develop methods to control polyphenol oxidase reaction. Essential oils of lemon grass, Cymbopogon citratus (D.C.) Stapf. and citronella, Cymbopogan nardus Rendle were found to inhibit the activity of polyphenol oxidase. Cinnamic acid inhibited the oxidation with an ID value of 0.351 (mg/ml). Citronella and lemongrass oils could be used as naturally occurring inhibitors for Polyphenol oxidase.
Use of waste generated from cinnamon bark oil (Cinnamomum zeylanicum Blume)extraction as a post harvest treatment for Embul banana
(Journal of Food , Agriculture and Environment, 2003) Ranasinghe, L.S.; Jayawardena, B.M.; Abeywickrama, K.P.
Waste water samples collected from a cinnamon bark oil distillery, was extracted and analyzed by Gas Chromatography. The major constituent of the extracted oil solution was cinnamaldehyde (66.2%). Previously isolated and identified fungal pathogens causing anthracnose and crown rot of Embul banana were treated in vitro with oil extract. The oil was fungistatic and fungicidal within the range of 0.64 mg/ml ? 1.00 mg/ml. Spraying Embul banana with emulsions of the oil extract prior to storage, controlled crown rot enabling banana to be stored for up to 14 days at ambient temperature (28 � 20 C) and 21 days at 140 C; 90% r.h. in modified atmosphere. A standard fungicide; benomyl treatment and control were included. There was no any detrimental effect of the physico-chemical properties such as percentage weight loss, fruit firmness, pH, total soluble solids and titratable acidity due to the treatment of oil extract. The evaluation of organoleptic properties showed higher acceptability of oil treated banana.