This review article presents the traditional and medicinal uses, and examines recent investigations on the biological activities of extracts, and chemicals identified from mangroves and mangal associates. Metabolites identified from mangrove plants are classified according to ‘chemical classes’, and some of their structures are illustrated. The article also presents some of the functions of the chemicals present and attempt to emphasize and create an awareness of the great of potential mangroves and mangal associates possess as a source of novel agrochemicals, compounds of medicinal value, and a new source of many already known biologically active compounds.

Bioactivities, bioactive compounds and chemical constituents of mangrove plants

Natural products from true mangrove flora: source, chemistry and bioactivities

Daphnane-type diterpene esters with cytotoxic and anti-HIV-1 activities from Daphne acutiloba Rehd.

TNF-α inhibitory diterpenoids from the Chinese mangrove plant Excoecaria agallocha L.

As a frontier organ, skin is exposed to different environmental and/or occupational chemicals which cause cutaneous cancers in experimental animals. In mice, 7,12-dimethylbenz[a]anthrancene (DMBA) and the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) are frequently used as skin model tumor initiator and promoter, respectively. The sequential administration of DMBA and TPA leads to the appearance of a large number of benign papillomas, of which some convert later into invasive squamous cell carcinomas (SCC). At the molecular level, initiation of carcinogenesis in mouse skin consists in the mutational activation of the Ha-ras oncoprotein. HA-RAS mutations are rare in human SCC, but HA-RAS-mutated tumors appear in melanoma patients treated with B-raf inhibitors, indicating that initiated, HA-RAS-mutated stem cells also reside in human skin. Similarly, UV-induced human SCC show footprint mutations in the tumor suppressor gene TP53 which are also observed in UV-induced mouse SCC. Strong species differences exist with respect to phorbol ester-mediated tumor promotion. While certain mouse strains are very susceptible, other rodent species are much less sensitive. Likewise, humans appear to be much more resistant to phorbol ester-mediated skin toxicity. Papilloma formation as a result of a chemical insult is uncommon in men, questioning the relevance of this preneoplastic lesion for humans. However, skin tumorigenesis in the experimental situation and in humans appears to follow common molecular mechanisms, even though there are species differences in the morphological correlates to the preneoplastic state. Therefore, we recommend not simply labeling them as irrelevant for human risk assessment.

Non-melanoma skin cancer in mouse and man.

From leaves of E. OPPOSITIFOLIA the irritant EXCOECARIA factor O (1) was isolated. Its structure 1 was shown to be identical with that of a factor obtained by transesterification of the cryptic EXCOECARIA factor group O (')(z) from the latex of the plant. From the non-irritant ethyl acetate fractions of the latices of E. AGALLOCHA, E. OPPOSITIFOLIA and E. BICOLOR, three TLC-homogenous non-irritant mixtures A (')(z), O (')(z) and B (')(z) were isolated and shown to represent non-separable cryptic EXCOECARIA factor groups containing 9,13,14-orthoesters of 5beta-hydroxyresiniferonol esterified in 20-position. The mixtures may be activated by mild treatment with sodium methoxide to generate mixtures of highly irritant factor groups A (z), O (z) and B (z) together with mixtures of aliphatic acid methylesters. The former may be separated partially by reversed phase TLC and yielded EXCOECARIA factors O (1), O (2), A (3), B (3) and B (4) together with residual non-separable factor groups. The structures 1-5 of the individual daphnane type irritant EXCOECARIA factors were elucidated by spectroscopic means. Their irritant activities were determined quantitatively on the mouse ear. The mixtures of methyl esters of aliphatic acids were analyzed by GC. Thus the complete structures of the cryptic factor groups from latex were deduced.

Investigations of medicinal plants of euphorbiaceae and thymelaeaceae occurring and used in Thailand; II. Cryptic irritants of the diterpene ester type from three Excoecaria species

H Hajiwangoh

Papers

Investigations of medicinal plants of euphorbiaceae and thymelaeaceae occurring and used in Thailand; II. Cryptic irritants of the diterpene ester type from three Excoecaria species