The microbial transformation of five flavans (1—5) by endophytic fungi isolated from the tea plant Camellia sinensis was investigated. It was found that the endophytic filamentous fungus Diaporthe sp. oxidized stereoselectively at C-4 position of (+)-catechin (1) and (−)-epicatechin (2) to give the correspondent 3,4-cis-dihydroxyflavan derivatives (6, 10), respectively. (−)-Epicatechin 3-O-gallate (3) and (−)-epigallocatechin 3-O-gallate (4) were also oxidized by the fungus into 3,4-dihydroxyflavan derivatives (10, 12) via (−)-epicatechin (2) and (−)-epigallocatechin (11), respectively. Meanwhile, (−)-gallocatechin 3-O-gallate (5), (−)-catechin (ent-1) and (+)-epicatechin (ent-2), which possess a 2S-phenyl substitution, resisted the biotransformation.

Two bisanthraquinones named (+)-epicytoskyrin (1) and (+)-1,1'-bislunatin (2) were produced by the endophytic fungus from a tea plant, which is a species closely related to Diaporthe phaseolorum strain sw-93-13. The chemical structures of the metabolites were elucidated on the basis of the physicochemical properties including the circular dichroism (CD) spectrum.

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Endophytic fungi are a group of fungi which grow inside the plant tissues without causing negative symptoms to the host plant and are able to produce biologically active substances. This research was carried out to evaluate the antibacterial and antioxidant activity of 40 endophytic fungi isolated from 10 species of medicinal plants collected from Palolo, Central Sulawesi. Thin layer chromatography (TLC) bioautography guided screenings were done to evaluate antibacterial and antioxidant activities. The antibacterial activity was done against Staphylococcus aureus InaCC-B5 and Escherichia coli InaCC-B4, while antioxidant activity was assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Minimum inhibitory concentrations (MICs) of active extracts were further evaluated against these bacteria, while half-maximal inhibitory concentration (IC50) of active extracts was determined by the microdilution broth method. The results of TLC bioautography screening showed 30 extracts inhibited the growth of S. aureus, 29 extracts inhibited the growth of E. coli, 27 extracts inhibited both S. aureus and E. coli, and 23 extracts posessed antioxidant activity. There were six extracts with MIC value of < 100 μg/ml against S. aureus and nine extracts with MIC value of < 100 μg/ml against E. coli. Six extracts indicated very strong antioxidant activity.

Lumnitzera littorea and Lumnitzera racemosa are mangrove species distributed widely along the Indonesian coasts. Besides their ecological importance, both are of interest owing to their wealth of natural products, some of which constitute potential sources for medicinal applications. We aimed to discover and characterize new anti-infective compounds, based on population-level sampling of both species from across the Indonesian Archipelago. Root metabolites were investigated by TLC, hyphenated LC-MS/MS and isolation, the internal transcribed spacer (ITS) region of rDNA was used for genetic characterization. Phytochemical characterization of both species revealed an unusual diversity in sulfated constituents with 3,3’,4’-tri-O-methyl-ellagic acid 4-sulfate representing the major compound in most samples. None of these compounds was previously reported for mangroves. Chemophenetic comparison of L. racemosa populations from different localities provided evolutionary information, as supported by molecular phylogenetic evidence. Samples of both species from particular locations exhibited anti-bacterial potential (Southern Nias Island and East Java against Gram-negative bacteria, Halmahera and Ternate Island against Gram-positive bacteria). In conclusion, Lumnitzera roots from natural mangrove stands represent a promising source for sulfated ellagic acid derivatives and further sulfur containing plant metabolites with potential human health benefits.