Microalgae are regarded as a rich trove of diverse secondary metabolites that exert remarkable biological activities. In particular, microalgae-derived bioactive phenolic compounds (MBPCs) are a boon to biopharmaceutical and nutraceutical industries due to their diverse bioactivities, including antimicrobial, anticancer, antiviral, and immunomodulatory activities. The state-of-the-art green technologies for extraction and purification of MBPCs, along with the modern progress in the identification and characterization of MBPCs, have accelerated the discovery of novel active pharmaceutical compounds. However, several factors regulate the production of these bioactive phenolic compounds in microalgae. Furthermore, some microalgae species produce toxic phenolic compounds that negatively impact the aquatic ecosystem, animal, and human life. Therefore, the focus of this review paper is to bring into light the current innovations in bioprospection, extraction, purification, and characterization of MBPCs. This review is also aimed at a better understanding of the physicochemical factors regulating the production of MBPCs at an industrial scale. Finally, the present review covers the recent advances in toxicological evaluation, diverse applications, and future prospects of MBPCs in biopharmaceutical industries.

Extraction and characterization of microalgae-derived phenolics for pharmaceutical applications: A systematic review.

Structural elucidation, Voltammetric detection of dopamine, Molecular docking and biological inspection of novel 4-aminoantipyrine derived Schiff bases in Co (II), Ni (II) and Cu (II) complexes

The search for novel sources of nutrients is among the basic goals for achievement of sustainable progress. In this context, microalgae are relevant organisms, being rich in high-value compounds and able to grow in open ponds or photobioreactors, thus enabling profitable exploitation of aquatic resources. Microalgae, a huge taxon containing photosynthetic microorganisms living in freshwater, as well as in brackish and marine waters, typically unicellular and eukaryotic, include green algae (Chlorophyceae), red algae (Rhodophyceae), brown algae (Phaeophyceae) and diatoms (Bacillariophyceae). In recent decades, diatoms have been considered the most sustainable sources of nutrients for humans with respect to other microalgae. This review focuses on studies exploring their bio-pharmacological activities when relevant for human disease prevention and/or treatment. In addition, we considered diatoms and their extracts (or purified compounds) when relevant for specific nutraceutical applications.

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Bioactive Molecules from Marine Diatoms and Their Value for the Nutraceutical Industry

Volatile oils from several Bupleuri radix (BR) are reported as potential sources of drugs. To provide evidence for the application of BR, the volatile oils from 19 batches of different species and habitats of BR including Bupleurum chinese DC. (BCD), Bupleurum scorzonerifolium Willd. (BSW), Bupleurum bicaule Helm (BBH), Bupleurum marginatum var. stenophyllum (Wolff) Shan et Y.Li (BMS), Bupleurum marginatum Wall.ex DC. (BMW) and Bupleurum falcatum L. (BFL) were investigated. The composition of BR volatile oils was determined by GC/MS. Samples were clustered by hierarchical cluster analysis (HCA). Fever was induced by Lipopolysaccharide (LPS), and antipyretic activities of BR volatile oils were evaluated with Chaihu injection (CI) as the positive control. The yields of volatile oils were among 360–5320 ppm. A total of 229 components were identified by GC/MS. Samples could be divided into 4 clusters by HCA. 4 representative samples, one for each cluster, were selected to further compare their antipyretic activities. For the highest content of volatile oil (5320 ppm) and the best activity, BSW has great potential for utilization.

Comparative Study on Volatile Oils among Bupleuri radix Species and Habitats: Yields, Chemical Characterization and Antipyretic Activities

Introduction and Aim: The antimicrobial peptides (AMPs) are generally found in invertebrates, mammals, birds, plants and insects. AMPs produced by insect parasitoids contribute to innate immunity to resist infection due to lack of adaptive immunity. T. chilonis is one of the most effective endoparasitoid wasps for controlling lepidopterous insects. Several attempts have been made to isolate, characterize and develop a commercially viable product of AMPs from various insect sources. The present study aimed to characterize AMP from T. chilonis for potential antimicrobial and anti-cancer properties. 
 
Methods: AMP was identified through T. chilonis transcriptome sequence and designed in silico and synthesized. Its purity was quantified using RP-HPLC, and the mass identified by mass spectrophotometry. LC/MS-MS was employed to predict the sequence and the BLAST program used to compare the sequence. AMP was tested for haemolytic activity and antimicrobial activity. Two pathogenic bacteria and fungal strains were used and IC50 values and MIC values were predicted against microbial strains. 
 
Results: Synthetic peptide was found to be 95% homogenous with molecular weight of 3.48 kD.  The peptide was identified to be a novel antimicrobial peptide consisting of 33 amino acid residues, and has a low computed instability index of -0.1.55 with high hydrophobic ratio of 27.27%. The antimicrobial activity revealed that T. chilonis antimicrobial peptide (TC-AMP) strongly inhibits the growth of selected human bacterial and fungal pathogens. While the haemolytic assay showed that the peptide did not obliterate human RBC in vitro. TC-AMP also showed an efficient inhibition of angiogenesis by in vivo model as evident by inhibition of vascularization.
 
Conclusions: AMP derived from the parasitoid has a potent antibiotic and anti-angiogenesis property. The peptide can be used as a potential antimicrobial and anticancer drug in near future with more detailed studies on its targeted applications.

Characterization and biochemical activities of novel functional antimicrobial peptide (AMP) from Trichogramma chilonis

Background: Nitzschia palea is a freshwater diatom species (Bacillariophyceae), is easy to cultivate, and is a primary producer of organic matters in aquatic environments. Materials and Methods: In this study, proximate composition in axenic culture of N. palea was determined, phenolic content and volatile compounds were determined for methanol and ethyl acetate extracts. Both the extracts were evaluated for eight different in vitro antioxidant and free radical scavenging activities. Macromolecular damage prevention properties were determined by electrophoretic methods, and antihemolytic activity was validated by lactate dehydrogenase assay, atomic force microscope, and scanning electron microscope image analysis. Results: Both the extracts showed antioxidant, macromolecular damage prevention, and antihemolytic properties. Among the two extracts, ethyl acetate extract showed high activity compared to methanol extract. Based on this result, ethyl acetate extract was evaluated for in vitro anti-inflammatory properties using RAW 264.7 cells. The extract showed IC50 value of 50.73 μg/mL and inhibition of inflammatory cytokines such as nitric oxide, tumor necrosis factor-alpha, and prostaglandin E2. The observed activity was correlated with identified important metabolites such as butyl isobutyl phthalate, pristane, and squalene of methanol extracts. Similar co-relation was observed for 7,9-di-tert-butyl-1-oxaspiro (4,5) deca-6,9-diene-2,8-dione, methyl palmitate, hentriacontane, and dibutyl phthalate were of ethyl acetate extract. Conclusion: The study concludes that N. palea has potentiality to isolate pharmacologically active metabolites using advanced chromatographic techniques, which can be useful in combating oxidative stress-related inflammatory diseases.

KR Sanjay

Papers

Volatile and phenolic compounds in freshwater diatom Nitzschia palea as a potential oxidative damage protective and anti-inflammatory source