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.

Manurung J, Siregar IZ, Kusmana C, Dwiyanti FG. 2017. Genetic variation of the mangrove species Avicennia marina in heavy metal polluted estuaries of Cilegon Industrial Area, Indonesia. Biodiversitas 18: 1109-1115. Mangrove forests are often facing various anthropogenic disturbances, particularly in the industrial area. However, information on the status of industrial heavy metal pollution and its impact on the genetic variation of mangrove species, such as Avicennia marina, particularly in Indonesian industrial area has not been assessed. In this study, the classification of heavy metals in two estuaries of Cilegon Industrial Area (Pelabuhan Warna Sari and Krakatau) and one estuary outside Cilegon Industrial Area (Pulau Sangiang) were determined by Sediment Quality Guidelines-States Environment Protection Agency (SQGs-USEPA). Furthermore, the genetic diversity of 72 individuals of A. marina in the three estuaries were examined using four microsatellite loci (M3, M64, M81 and M98). The results showed that Krakatau area was the heavily polluted estuary based on SQGs-USEPA and have a lower genetic variation (He= 0.54) than Pelabuhan Warna Sari (moderately polluted, He= 0.56) and Pulau Sangiang (non-polluted, He= 0.60) suggesting a notable of deficiencies of genetic variation of A. marina in heavy polluted estuary compared to moderately and non-polluted estuary. Considering the low level of genetic variation in heavily polluted area, transplantation among estuaries and introduction of propagules from non-polluted estuary or other regions are needed as one of the conservation efforts.

The Indonesian Archipelago accommodates the largest mangrove area in Southeast Asia and possesses the world's richest composition of mangrove species. The archipelago comprises areas of the biogeographic regions Sunda and Wallacea, separated by Wallace's line. Here, we used the true mangrove species Lumnitzera littorea and Lumnitzera racemosa as a study case for understanding the effects of phylogeographic history, sea surface currents, and geographical distance on genetic diversity and genetic structure. We sampled 14 populations of L. littorea (N = 106) and 21 populations of L. racemosa (N = 152) from Indonesia and used 3122 and 3048 SNP loci, respectively, genotyped using the ddRADseq approach. We assessed genetic diversity, genetic structure, and effective dispersal of the populations and related them to geographical distance and sea surface currents. Our study revealed low levels of genetic variation at the population level in Lumnitzera. Pronounced genetic differentiation between populations indicated two phylogroups in both species. While in L. littorea the two phylogroups were largely separated by Wallace's line, L. racemosa showed a northwest vs. southeast pattern with strong mixture in Wallacea. Our findings provide novel insights into the phylogeography of the mangrove genus Lumnitzera and the role of sea surface currents in the Indonesian Archipelago.