Chemical constituents from green alga Ulva pertusa / 中草药

Objective To investigate the chemical constituents from the ethanol extract of Ulva pertusa. Methods The compounds were isolated and purified by chromatography on silica gel, ODS, Diaion HP-20, Sephadex LH-20, and preparative HPLC methods. Their structures were elucidated on the basis of spectral data. Results Eighteen compounds were isolated and identified as isophitol (1), indole-3-carboxylic acid (2), 1-O-palmitoyl-3-O-(6'-sulfo-α-D-quinovopyranosyl) glycerol (3), (2S)-1-O-palmitoyl-3-O-[α-D- galactopyranosyl-(1→2)-β-D-galactopyranosyl] glycerol (4), 3-methylsulfoxypropionic acid (5), 3-chloropropionic acid (6), tyrosol (7), 4-hydroxybenzoic acid (8), 4-hydroxyphenylacetic acid (9), 6-vinyl hexanolide (10), loliolide (11), annuionone D (12), azelaic acid (13), succinic acid (14), 8-hydroxy-(6E)-octenoic acid (15), 3-ethoxypropionic acid (16), n-butyl β-D-fructopyranoside (17), and n-butyl pyroglutamate (18). Conclusion Compounds 1-16 are isolated from this alga for the first time, and compounds 5, 6, 10, 15, and 16 are obtained from natural products for the first time. Compounds 17 and 18 are artifacts of isolation from β-D-fructopyranoside and pyroglutamic acid.

An antithrombin-dependent sulfated polysaccharide isolated from the green alga Caulerpa cupressoides has in vivo anti- and prothrombotic effects / Um polissacarídeo sulfatado dependente de antitrombina isolado da alga verde Caulerpa cupressoides possui efeitos anti- e pró-trombótico in vivo

Red algae sulfated polysaccharides (SPs) have been widely described as anticoagulant and antithrombotic agents; however no description of antithrombotic activity regarding green algae SPs has been reported. Caulerpa cupressoides (Chlorophyta) has three different SPs fractions (SP1, SP2 and SP3). We investigated the effects of SP2 on thrombin activity by antithrombin and in an experimental model of venous thrombosis in rats. The inhibition of thrombin assay was evaluated using antithrombin (AT) in the presence of SP2 and the antithrombotic activity was investigated in rats with thromboplastin as the thrombogenic stimulus. The anticoagulant effects of SP2 are suggested be due to the potentiation of thrombin inhibition by antithrombin (IC50 ~ 10.0µg mL-1) and this mechanism of interaction is different when compared to other studied Caulerpa polysaccharides. SP2 exhibited antithrombotic effects at doses of 1.0 and 2.0mg kg-1 body weight, but at higher doses (>2.0mg kg-1 body weight) this polysaccharide revert the antithrombotic property. No hemorrhagic effect (2.0mg kg-1) was observed. As occurs with red algae SPs, these results indicate that green algae SPs are also capable of exhibiting different in vivo properties.

Os polissacarídeos sulfatados (PSs) de algas vermelhas têm sido relatados mundialmente como agentes anticoagulantes e antitrombóticos. Entretanto, nenhuma descrição de atividade antitrombótica tem sido relacionada com os PSs de algas verdes. A clorofícea Caulerpa cupressoides possui três frações de PSs (PS1; PS2 e PS3). Dessa forma, objetivou-se investigar os efeitos da fração PS2 sobre a atividade da trombina por antitrombina e usando um modelo experimental de trombose venosa em ratos. O ensaio de inibição da trombina foi avaliado usando a antitrombina (AT) na presença de PS2 e a atividade antitrombótica foi investigada em ratos, usando a tromboplastina como o estímulo trombogênico. Os efeitos anticoagulantes de PS2 devem-se provavelmente à sua potência de inibir a trombina mediada pela AT (IC50 ~ 10,0µg mL-1) e esse mecanismo de interação é diferente, comparado ao de outros polissacarídeos de Caulerpa estudados. PS2 exibiu efeitos antitrombóticos nas doses de 1,0 e 2,0mg kg-1 peso corpóreo, mas em doses mais elevadas (>2,0mg kg-1 peso corpóreo) esse polissacarídeo exibe efeitos pró-trombóticos. Também não foi observado nenhum efeito hemorrágico (2,0mg kg-1). Assim como ocorre com os PSs de algas vermelhas, os resultados indicam que os PSs de algas verdes também possuem atividades biológicas distintas in vivo.

Control of sporulation in the filamentous cyanobacterium A nabaena torulosa.

In the cyanobacterium Anabaena torulosa, sporulation occurred even during the logarithmic growth phase. Sporulation was initiated by differentiation of the vegetative cell on one side, adjoining the heterocyst followed by differentiation of the vegetative cell on the other side. Subsequently, spores were differentiated alternately on either side to form spore strings. The sequence of sporulation supports the previous notion that a gradient of spore maturation exists in cyanobacteria and also indicates that the gradient is manifested unequally on either side of heterocysts. Sporulation was absent or negligible in a minerally enriched medium but ocurred readily in a minimal medium. The extent of sporulation was inversely related to phosphate concentration. Sporulation was enhanced at higher temperature. Incandescent light, but not fluorescent light, greatly stimulated sporulation suggesting possible involvement of red light in spore differentiation. Addition of filtrate, from 5 to 8 day old cultures, to freshly inoculated A. torulosa greatly enhanced sporulation indicating the influence of extracellular products in spore formation.

Microbial load in mass cultures of green algae Scenedesmus acutus and its processed powder.

Microbial contamination in cultures of the alga, Scenedesmus acutus raised in outdoor open tanks and also in the processed powder of the alga was monitored; The total bacterial population increased with time during the growth period of six days. When a combination of molasses and carbondioxide was employed as carbon source for this alga, the bacterial load increased to 10 colony forming units/ml. Yeast, molds and also coliforms were quantitated. Drum-drying the algae drastically reduced the bacterial load and storing the algal powder for a period of over 3 months did not increase the bacterial load. Pathogens like Salmonella and Staphylococcus were not detectable either in the open cultures or in the drumdried algal powder. Although there are not set standards available in literature on the permissible level of the microbial contamination in algal biomass for use in foods, the microbial load appears to be within the limits of permissible levels stipulated by Indian Standard Institution standards for baby foods.

Action of 2,4-dichlorophenoxyacetic acid and rifampicin on heterocyst differentiation in the blue-green alga, Nostoc linckia.

2,4-Dichlorophenoxyacetic acid, a commonly used herbicide, increased the growth of the filamentous blue-green alga, Nostoc linckia at doses upto 100 μg /ml. The herbicidetreated N2-cultures showed enhanced heterocyst frequency and N2-growth. Thus, the herbicide stimulated algal growth at the expense of molecular nitrogen under aerobic growth conditions. Rifampicin caused chain formation of heterocysts. This was effectively counteracted by 2,4-dichlorophenoxyacetic acid, suggesting a biological interaction between them at the level of the heterocyst spacing control mechanism.