State-of-the-art review on the ecotoxicology, health hazards, and economic loss of the impact of microcystins and their ultrastructural cellular changes.

Cyanobacteria are ubiquitously globally present in both freshwater and marine environments. Ample reports have been documented by researchers worldwide for pros and cons of cyanobacterial toxins. The implications of cyanobacterial toxin on health have received much attention in recent decades. Microcystins (MCs) represent the unique class of toxic metabolites produced by cyanobacteria. Although the beneficial aspects of cyanobacterial are numerous, the deleterious effect of MCs overlooked. Several studies on MCs evidently reported that MCs exhibit a plethora of harmful effect on animals, plants, and cell lines. Accordingly, numerous histopathological studies have also found that MCs cause detrimental effects to cells by damaging cellular organelles, including nuclear envelope, Golgi apparatus, endoplasmic reticulum, mitochondria, plastids, flagellum, pilus membrane structures and integrity, vesicle structures, and autolysosomes and autophagosomes. Such ultrastructural cellular damages holistically influence the morphological, biochemical, physiological, and genetic status of the host. Indeed, MCs have also been found to cause the deleterious effect to different animals and plants. Such deleterious effects of MCs have greater impact on agriculture, public health which in turn influences ecotoxicology and economic consequences. The impairments correspond to oxidative stress, organ failure, carcinogenesis, aquaculture loss, with an emphasis for blooms and respective bioaccumulation prospects. The preservation of mortality among life forms is addressed in a critical cellular perspective for multitude benefits. The comprehensive cellular assessment could provide opportunity to develop strategy for therapeutic implications.

Assessment of Tissue Specific Distribution and Seasonal Variation of Alkaloids in Alstonia scholaris.

Alstonia scholaris is a well-known source of alkaloids and widely recognized for therapeutic purposes to treat the ailments in human and livestock. However, the composition and production of alkaloids vary due to tissue specific metabolism and seasonal variation. This study investigated alkaloids in leaves, stems, trunk barks, fruits, and flowers of A. scholaris. The impact of seasonal changes on the production of alkaloids in the leaves of A. scholaris was also investigated. One and two-dimensional Nuclear Magnetic Resonance (NMR) experiments were utilized for the characterization of alkaloids and total eight alkaloids (picrinine, picralinal, akuammidine, 19 S scholaricine, 19,20 E vallesamine, Nb-demethylalstogustine N-Oxide, Nb-demethylalstogustine, and echitamine) were characterized and quantified. Quantitative and multivariate analysis suggested that the alkaloids content is tissue specific, illustrating the effect of plant tissue organization on alkaloidal production in A. scholaris. The results suggest that the best part to obtain alkaloids is trunk barks, since it contains 7 alkaloids. However, the best part for isolating picrinine, picralinal, akuammidine, 19 S scholaricine, and 19,20 E vallesamine is fruit, since it shows highest amount of these alkaloids. Undoubtedly, NMR and statistical methods are very helpful to differentiate the profile of alkaloids in A. scholaris.

Antiplasmodial activity of extracts of 25 cyanobacterial species from coastal regions of Tamil Nadu.

CONTEXT: Marine cyanobacteria offer considerable potential to isolate new antimalarials to meet a pressing need of our times. OBJECTIVE: To explore the antiplasmodial properties of marine cyanobacteria. MATERIALS AND METHODS: Cyanobacterial samples collected from the coastal regions of Tamil Nadu were identified using light microscopy, and the strains were cultivated in ASN-III medium. Organic extracts (0-100 µg mL(-1)) of 25 in vitro mass-cultivated cyanobacteria, prepared using methanol: chloroform mixture (1:1 v/v) were evaluated for their antiplasmodial activity against chloroquine-sensitive and -resistant strains of Plasmodium falciparum by fluorescence-based SYBR Green I assay where chloroquine was used as a control. To detect the toxic effects of cyanobacterial extracts against red blood cells, the invasion, maturation, and growth rate of malarial parasites in cyanobacterial extracts pre-treated versus untreated erythrocytes were quantified microscopically. Mammalian cell line (HeLa) was used to determine cyanobacterial extract toxicity using the MTT assay. RESULTS: The extracts of Lyngbya aestuarii Liebm. ex Gomont CNP 1005 (C12) Oscillatoria boryana BDU 91451 (C22) and Oscillatoria boryana Bory ex Gomont BDU 141071 (C18) showed promising antiplasmodial activity (IC50 = 18, 18, and 51 µg mL(-1) respectively) against Pf3D7. Pretreatment of red blood cells with IC100 of C12, C18, and C22 (40, 100, and 40 µgmL(-1), respectively) did not significantly influence the invasion, maturation, and growth rate of malarial parasites in comparison with untreated RBC controls suggesting a lack of toxicity to host cells. MTT assay based IC50 (>200 µg mL(-1)) of these extracts against HeLa cell line also indicates their high selectivity against the malaria parasite. DISCUSSION AND CONCLUSION: These exploratory studies suggest the possibilities of development of new antimalarial compounds from marine cyanobacteria.