Bioactivity and Mycochemical Profile of Extracts from Mycelial Cultures of Ganoderma spp.

Fungal mycelium cultures are an alternative to natural sources in order to obtain valuable research materials. They also enable constant control and adaptation of the process, thereby leading to increased biomass growth and accumulation of bioactive metabolites. The present study aims to assess the biosynthetic potential of mycelial cultures of six Ganoderma species: G. adspersum, G. applanatum, G. carnosum, G. lucidum, G. pfeifferi, and G. resinaceum. The presence of phenolic acids, amino acids, indole compounds, sterols, and kojic acid in biomass extracts was determined by HPLC. The antioxidant and cytotoxic activities of the extracts and their effects on the inhibition of selected enzymes (tyrosinase and acetylcholinesterase) were also evaluated. The total content of phenolic acids in the extracts ranged from 5.8 (G. carnosum) to 114.07 mg/100 g dry weight (d.w.) (G. pfeifferi). The total content of indole compounds in the extracts ranged from 3.03 (G. carnosum) to 11.56 mg/100 g d.w. (G. lucidum) and that of ergosterol ranged from 28.15 (G. applanatum) to 74.78 mg/100 g d.w. (G. adspersum). Kojic acid was found in the extracts of G. applanatum and G. lucidum. The tested extracts showed significant antioxidant activity. The results suggest that the analyzed mycelial cultures are promising candidates for the development of new dietary supplements or pharmaceutical preparations.

Uji Aktivitas Ekstrak Daun Dan Akar Singawalang (Petiveria alliaceae) Terhadap Penghambatan Tirosinase

Tyrosinase is an enzyme that plays a role in the formation of skin pigments from a person because it is involved in the process of melanogenesis. Tyrosinase plays a very important role in the skin depigmentation process, there are several attempts to inhibit the skin depigmentation process, one of which is by inhibiting tyrosinase. Research on the leaves and roots of singawalang (Petiveria alliacea) was conducted to determine the potential as a tyrosinase inhibitor. Leaves and root extracts of singawalang were macerated with ethanol, then tested for identification of secondary metabolites. Singawalang leaves extract contains alkaloids, tannins and terpenoids while singawalang root extract contains alkaloids, flavonoids, tannins and terpenoids. Tyrosinase inhibitory activity used the microplate reader ELISA technique at a wavelength of 492 nm. Tests were carried out on kojic acid as a comparison and L-DOPA as a substrate. The results of the tyrosinase inhibition activity test for the extracts of singawalang leaves, singawalang roots and kojic acid, IC50 were 9.817 mg / mL, 4.987 mg / mL and 0.092 mg / mL, respectively.

ANTI-TYROSINASE AND ANTI-OXIDANT POTENTIAL OF METHANOLIC EXTRACTS OF SELECTED CITRUS BERGAMIA AND FICUS CARICA PARTS

Tyrosinase is a key enzyme in melanogenesis and its high activity leads to increasedpigmentations causing skin disorder like freckles, melanosoma and black spot. Therefore to search for new tyrosinase inhibitors is desirable. In present study, methanolic (MeOH) extracts from leaves, fruit peel and pulp of Citrus bergamia (CB) and, leaves and fruitof Ficus carica (FC) were prepared which were further process for fractional ethyl alcohol (EA), n-hexane (n-Hx) and chloroform (CHCl3)extractions (total 20 extracts) aiming to test their anti-tyrosinase potential, in-vitro. Our results confirmed that all MeOH FC and CB extracts showed significant anti-oxidant activity with IC50 range of 461.9 ± 16.1µg/ml to 2324.4 ± 116.1 µg/ml. Moreover, CB and FC all 20 extracts have significant anti-tyrosinase activity with IC50 range of 13.9 ± 0.5 µg/ml to 320.5 ± 3.3 µg/ml. Interestingly, CB MeOH-EA peel and leaf extracts showed tyrosinase inhibition (IC50) 13.9 ± 0.5 µg/ml and 17.2 ± 0.8 µg/ml, respectively) is better than all other tested extracts and positive control kojic acid (IC50=18.75±5.29µg/ml). Thus, CB MeOH-EA peel extract with lowest IC50 value among all the tested extracts and kojic acid is proposed as potent candidate to control tyrosinase rooted hyperpigmentation.

Heterologous expression of a polyketide synthase ACRTS2 in Aspregillus oryzae produces host selective ACR-toxins: Co-production of minor metabolites

Previously, we succeeded to produce the core structure of the host-selective ACR-toxin (1) on brown leaf spot on rough lemon when the polyketide synthase ACRTS2 gene was heterologously expressed in Aspergillus oryzae (AO). To confirm the production of 1 in AO, the detection limit and suppressing decarboxylation were improved, and these efforts led us to conclude the direct production of 1 instead of its decarboxylation product. During this examination, minor ACR-toxin-related metabolites were found. Their structure determination enabled us to propose a decarboxylation mechanism and novel branching route forming byproducts from the coupling of the dihydropyrone moiety of 1 with the acetaldehyde and kojic acid abundant in AO. The involvement of putative cyclase ACRTS3 in the chain release of linear polyketide was excluded by the co-expression analysis of ACRTS2 and ACRTS3. Taken together, we concluded the production of 1 in AO is solely responsible for ACRTS2.