Carrageenophyte farming is an expanding economical activity in North Borneo Island, Malaysia. During routine monitoring of "ice-ice" disease and epiphyte outbreak at commercial farms, it was apparent that culture lines were heavily (60-80%) infested with biofoulers, particularly Acanthophora spp. and Laurencia majuscula. However, only L. majuscula showed dominance and flourished even during "ice-ice" disease outbreak. Presence of chemical defense against seaweed pathogens was investigated in two populations of L. majuscula collected from three major carrageenophyte farms in two districts; (A) Lohok Butun, Selakan Island, and Bum-Bum Island, in Semporna district, and (B) Telutuh, Carrington Reef, and Balambangan Island, in Kudat district. The first population contained elatol (1), and iso-obtusol (2), and, second population contained (Z)-10,15-dibromo-9-hydroxy-chamigra-1,3(15),7(14)-triene (3) and (E)-10-15-dibromo-9-hydroxy-chamigra-1,3(15),7(14)-triene (4), as their antibacterial metabolites. All four metabolites showed highly selective inhibition against "ice-ice" disease bacteria compared to human pathogens at 30µg disk −1 . In addition, seasonal variation of these compounds at two representative farms (Selakan Island [P-1] and Balambangan Island [P-2]) revealed a 120-170% increase in concentration during "ice-ice" disease outbreak. Microscopy of fresh specimens showed the presence of corps en cerise, which is the synthesis and storage site of halogenated metabolites at superficial cortical cells, branch tips, and trichoblasts. This suggests the importance of these metabolites as defense chemicals against "ice-ice" disease bacteria in L. majuscula that grows on seaweed culture lines.
As part of our continuous effort in search of bioactive secondary metabolites from marine organisms, we studied a specimen of red algae, Laurencia nangii Masuda from Banggi Island, Kudat District, Sabah. One C-15 acetogenin was isolated and identified as Z-dihydrorhodophytin (1, 15%). This compound showed 100% inhibition against the tested bacteria at 30 gdisc -1 . MIC values for Salmonella enteritidis, Vibrio cholerae and Staphalococcus aereus were 1.25 gdisc -1 , 2.25 gdisc -1 and 2.25 gdisc -1 , respectively; while Escherichia coli, Salmonella typhii and Salmonella thphymunium were inhibited at MIC value of 7.25 gdisc -1 . This study showed that Z-dihydrorhodophytin (1) has significant antibacterial activity against the tested food pathogens and may have potential to be used as lead pharmaceutical drug candidate in combating "antibiotic resistant bacteria". ABSTRAKSehubungan dengan usaha kami untuk mengkaji sebatian sekunder bioaktif daripada organisma marin, kami telah menyelidik satu spesimen alga merah, Laurencia nangii Masuda dari Pulau Banggi, Kudat, Sabah. Satu sebatian C15-acetogenin telah dipencilkan dan dikenalpasti sebagai Z-dihydrorhodophytin (1, 15%). Sebatian ini menunjukkan 100% perencatan pada 30 gdisc -1 . Nilai MIC bagi Salmonella enteritidis, Vibrio cholerae dan Staphalococcus aereus adalah 1.25 gdisc -1 , 2.25 gdisc -1 dan 2.25 gdisc -1 , manakala nilai untuk Escherichia coli, Salmonella typhii dan Salmonella thphymunium adalah 7.25 gdisc -1 . Kajian ini menunjukkan bahawa Zdihydrorhodophytin (1) dapat merencatkan bakteria yang diuji dengan signifikan dan mempunyai potensi untuk dijadikan sebagai "lead drug" farmaseutikal dalam usaha mengawal "bakteria rintang antibiotik".(Keywords: Laurencia nangii, C15-acetogenin, antibiotic resistant bacteria)
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.