Abstract. Swantara IMD, Bawa IGAG, Suprapta DN, Agustina KK, Temaja IGRM. 2020. Identification Michelia alba barks extract using Gas Chromatography-Mass Spectrometry (GC-MS) and its antifungal properties to inhibit microbial growth. Biodiversitas 21: 1541-1550. Fungicides are substances that inhibit the growth or kill the pathogenic fungi. A substance can be categorized as a fungicide if it shows antifungal activity. This activity is resulting from bioactive compounds derived from the secondary metabolites. Michelia alba bark’s extract could inhibit the growth of Curvularia verruculosa, the cause of leaf spot disease on rice. The purpose of this study was to analyze chemical compounds of bark extract which inhibit the growth of C. verruculosa. The extraction of bark metabolites of M. alba was done using methanol as the solvent. The inhibitory test of the extract was carried out by the diffusion well method on Potato Dextrose Agar (PDA) medium. Analysis of chemical compounds of the M. alba extract was carried out in Gas chromatography-mass spectroscopy. The results of inhibitory test found that the M alba bark extract inhibits the C. verruculosa with the inhibition zone as wide as 36 mm in diameter. The majority of chemical compounds identified from the M. alba extract consisted of 10 compounds, namely: Hexadecanoic acid, methyl ester; 4H-tomentosine; 4H-tomentosine (compound isomer 2); 3-hydroxy pregn-4-ene-20-one; Tomentosine; 2-hydroxy tomentosine; Tert-butyl-2-aminophenylcarbamol; 2H-cyclohepta [b] furan-2-one, 3,3a, 4,7,8,8a-hexahydro-7-methyl-3-methylene-6-(2-formil-3-oxobutyl)-; Isoxanthanol and Xanthanol. To conclude, this extract is useful to treat C. verruculosa that causes leaf spot disease on rice.

A multilocational field trial was conducted to investigate the effect of some plant extracts (Bolanite aegyptica, Eucalyptus camaldulensis and Citrus aurantium) and a synthetic antibiotic (Streptomycin) on the incidence and severity of angular leaf spot on five cotton geno-types namely SAMCOT-8, SAMCOT-9, SAMCOT-10, SAMCOT-11 and SAMCOT-12 in Yola and Jalingo, both located in the northern guinea savannah zone of Nigeria. The experiment was carried out on a split-plot design having three replications with cotton genotypes on the main plots and plant extracts on the sub-plots. Data collected on the incidence and severity of the disease were analysed using the Generalized Linear Model procedure and means separation at 5% level of probability by Duncan Multiple Range Test. Findings of the study revealed that Streptomycin and Bolanite aegyptiaca were able to reduce the disease incidence by 18.12% from 58.69% in Yola at 13 WAS. In Jalingo however, B. aegyptiaca was found to have re-duced the disease severity from 52.12% to 19.69% at 13 WAS. SAMCOT-8 consistently recorded lower incidence and severity means in Yola and Jalingo of 47.96%; 59.12% and 40.82%; 39.70% while SAMCOT-12 recorded higher means of 53.29%; 59.82% and 48.03%; 46.70% respectively.

The bark extract of Michelia alba was able to inhibit the growth of Curvularia verruculosa fungus which was isolated from leaf spot disease in rice. Separation of the active compound was carried out by column chromatography method using the stationary phase of silica gel and the mobile phase of a mixture of n-hexane-acetone (3: 1). Separation of the active extracts resulted in 10 combined fractions, where 4 fractions showed very strong inhibition, namely the HAE fraction (31.50 mm), HAF (30.13), HAG (48.50), and HAH (34.88). The composition of terpenoid compounds in these fractions was analyzed by Gas Chromatography-Mass Spectrometry. The compound ledenoxid (II) and isoaromadendrene epoxide werefound in almost all of the active fractions, while spathulenol wasfound in the HAF and HAG fractions. Other terpenoid compounds found werecis-farnesol, trans-p-mentha-1 (7), 8-dien-2-ol, and neoclovenoxid-alcohol in the HAE fraction, (-)-caryophyllene oxide and tomentosin in the fraction of HAG. All of the detected terpenoid compounds were compounds from the sesquiterpene group. Keywords: Michelia alba extract, inhibitory power, Curvularia verruculossa, sesquiterpenes

Sembukan is a wild plant that is often attached to the house fenced and has a lot of chemicals compound, including essential oil. This study aims to determine the active compounds as antibacterial of sembukan essential oil. One point four mililitres of essential oil was obtained by steam distillation. The essential oils were then tested for antibacterial activity against Escherichia coli and Stapylococcus aureus using the well diffusion method in gel. Identification of the essential oils conducted using Chromatography Gas – Mass Spectroscopy (GC-MS). The results of this study indicated that the essential oils did not have specific antibacterial activity against the bacteria tested. Compounds contained in the essential oils of sembukan were hydrogenated Linalool, Eugenol, Tetradecane, Heksadecane, and Dibutyl phthalate.

The purpose of this study was observe the antifungal activity of the bark extract of Michelia alba against Curvularia verruculosa fungal of the cause of leaf spot disease in rice. The antifungal activities was carried out using the diffusion well, colony, biomass formation methods. The bark extract of Michelia alba has showed the antifungal activity against Curvularia verruculosa fungal with a minimum inhibition concentratiotn value to be 0.5%. The bark extract of Michelia alba with 2.0% concentration can strongly inhibit the growth of C. Verruculosa with inhibiting capabality is 33.17 mm. This extract at 0.6% concentration was able to completely inhibit the growth of fungal colony and at 2.0% concentration has been able to inhibit completely the biomass formation of C. Verruculosa fungal for a 14-day period of incubation.