Antifungal activity and molecular identification of endophytic fungi from the angiosperm Rhodomyrtus tomentosa

Problems associated with fungal resistance to antifungal agents are increasing worldwide. There is need to find sources of novel antifungal drugs and endophytic fungi could be another interesting source. In this study, 213 culturable endophytic fungi isolated from leaves and branches of Rhodomyrtus tomentosa from Thailand were screened for their ability to produce antifungal agents. Crude extracts from 177 out of 213 fungal isolates exhibited inhibitory activity against human pathogenic fungi, evaluated by a microbroth dilution method. Of the 349 active extracts out of 617 extracts tested, 43.5% inhibited Penicillium marneffei; 16.5 to 20.8% inhibited two strains of Cryptococcus neoformans; 6.0% Microsporum gypseum; 5.0% Candida albicans, with minimal inhibitory concentrations (MIC) of 1 to 200 μg/ml. 22 endophytic fungi showing strong antifungal activity (MICs of 1 to 8 μg/ml) were identified by morphological and molecular methods. They mainly belonged to the genera Colletotrichum, Diaporthe, Guignardia and Phomopsis. The results of this work indicate that endophytic fungi from R. tomentosa can be a good source of potential antifungal natural products.Keywords: Rhodomyrtus tomentosa, antifungal activity, endophytic fungi, molecular identificatio

การศึกษาฤทธิ์ทางเภสัชวิทยาของสมุนไพรที่ผู้ป่วยเอดส์ใช้รักษาตนเอง

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Lovastatin Production by Aspergillus sclerotiorum Using Agricultural Waste

Pozadina istraživanja. Lovastatin je poznati lijek za liječenje hiperkolesterolemije. Međutim, cijena njegove prozvodnje je još uvijek visoka. Stoga je potrebno pronaći jeftiniji izvor ugljika za proizvodnju lovastatina. Eksperimentalni pristup. Ispitana je mogućnost uporabe četiriju različitih uzoraka poljoprivrednog otpada, i to: stabljika kukuruza, rižinih ljusaka, divlje vrste šećerne trske i uljnog taloga zaostaolog nakon proizvodnje sojinog ulja, kao supstrata za proizvodnju lovastatina submerznim uzgojem i fermentacijom na čvrstoj podlozi s pomoću novog soja plijesni Aspergillus sclerotiorum PSU-RSPG 178. Rezultati i zaključci. Među ispitanim supstratima i metodama uzgoja, najveći je prinos lovastatina od 0,04 mg/g suhe tvari dobiven uzgojem na uljnom talogu nastalom pri proizvodnji sojinog ulja, pri temperaturi od 25 °C tijekom 14 dana fermentacije na čvrstoj podlozi. Stoga su tom talogu kao izvori ugljika zasebno dodani glukoza, pšenično brašno, elementi u tragovima, palmino ulje, urea i melasa. Dodatkom palminog ulja prinos lovastatina povećao se na 0,99 mg/g. Optimalni uvjeti pri kojima je dobiveno (20±2) mg/g lovastatina nakon 18 dana fermentacije na čvrstoj podlozi bili su: uljni talog s udjelom vlage u suhoj tvari od 80 %, omjer taloga (u g) i micelijskih diskova od 1:4, te omjer taloga (u g) i palminog ulja (u mL) od 1:2. Osim toga, zaključeno je da prinosi lovastatina dobiveni fermentacijom na čvrstoj podlozi od svježeg ili sušenog uljnog taloga nisu bili bitno različiti. Novina i znanstveni doprinos. Zaključili smo da se plijesan Aspergillus sclerotiorum PSU-RSPG 178 može upotrijebiti za proizvodnju lovastatina na podlozi od uljnog taloga nastalog pri proizvodnji sojinog ulja obogaćenoj palminim uljem kao izvorom ugljika.Research background. Lovastatin is a well-known drug used to reduce hypercholesterolaemia. However, the cost of lovastatin production is still high. Therefore, alternative low-cost carbon sources for the production of lovastatin are desirable. Experimental approach. Four different agricultural wastes, namely corn trunks, rice husks, wild sugarcane, and soya bean sludge, were tested separately as substrates to produce lovastatin using a new fungal strain, Aspergillus sclerotiorum PSU-RSPG 178, under both submerged and solid-state fermentation (SSF). Results and conclusions. Of these substrates and cultivation systems, soya bean sludge gave the highest lovastatin yield on dry mass basis of 0.04 mg/g after 14 days of SSF at 25 °C. Therefore, the soya bean sludge was separately supplemented with glucose, wheat flour, trace elements, palm oil, urea and molasses. The addition of the palm oil enhanced the lovastatin yield to 0.99 mg/g. In addition, the optimum conditions, which gave a lovastatin yield of (20±2) mg/g after 18 days of SSF, were soya bean sludge containing 80 % moisture (dry basis) at a ratio of soya bean sludge (g) to mycelial agar plugs of 1:4, and a ratio of soya bean sludge (g) to palm oil (mL) of 1:2. Besides, the lovastatin yields obtained from SSF using fresh or dry soya bean sludge were not significantly different. Novelty and scientific contribution. We conclude that A. sclerotiorum PSU-RSPG 178 has a good potential as an alternative strain for producing lovastatin using soya bean sludge supplemented with palm oil as a carbon source

Souwalak Phongpaichit

PSU Collaborative Research Fun

Rotenoids from the flowers of Millettia brandisiana

From the hexane extract of the flowers of Millettia brandisiana (Leguminosae), four rotenoids, α- toxicarol (1), 12a-hydroxy-α-toxicarol (2), 6-deoxyclitoriacetal (3) and 6a,12a-dehydro-α-toxicarol (4) wereisolated. Their structures were determined by spectroscopic methods. In addition, rotenoids 2 and 3 were evaluated for antimicrobial activity and found to be inactive at 128 μg/ml