In vitro antiplasmodial activity of methanolic extracts from seaweeds of South West Coast of India

Synthesis of Zinc Oxide Nanoparticles From Aqueous Extract of Avicennia marina Mangrove Leaves and Their Antibacterial Activities Against Oral Pathogens

Introduction The field of nanotechnology is currently being extensively researched. Nanoparticles (NPs) are used in many fields, such as engineering and medicine, owing to their nanoscale dimensions. Zinc (Zn) appears to be the most desirable metal NP, as it is being applied in various drug delivery systems and other fields. The green synthesis of the NPs used in this study makes it affordable and nonpolluting. Avicennia marina leaves possess antimicrobial properties and a high secondary metabolite content. This study aimed to synthesize ZnO NPs from the aqueous extracts of A. marina mangrove leaves and assess their antibacterial activities against oral pathogens. Methodology The leaves of A. marina were dried to obtain a preprocessed powder, and from that, an aqueous extract was prepared. ZnO NPs were then synthesized by adding the aqueous extract to 100 mL of ZnS solution and mixing it in an orbital shaker. They were observed both visually and by ultraviolet (UV) spectrophotometry to confirm their synthesis. The antibacterial properties of these ZnO NPs were assayed using the disc diffusion method on three different oral bacterial strains (Streptococcus mutans, Staphylococcus aureus, and Klebsiella sp.).  Results For the synthesis process, it was seen that zinc oxide (ZnO) NPs exhibited a deepening in coloration. Additionally, the UV spectrum analysis revealed a notable absorbance value of 1.2 at a wavelength of 320 nm. The antibacterial efficacy against S. mutans, S. aureus, and Klebsiella sp. was assessed by measuring the zone of inhibition in diameter. At a dosage of 100 µg/mL of ZnO NPs, the inhibition zones were found to be 7.5 ± 0.2, 9.5 ± 0.5, and 9.5 ± 1.2 mm for S. mutans, S. aureus, and Klebsiella sp., respectively. Similarly, at a concentration of 75 µg/mL, the inhibition zones were measured to be 7 ± 0.25, 9 ± 1, and 7.5 ± 0.5 mm for the respective bacterial strains. Conclusions This study synthesizes ZnO NPs using A. marina leaf aqueous extract in a sustainable and eco-friendly manner. The ZnO NPs' antibacterial activities against oral infections indicate their use in dental products. These NPs have promising potential for nanomedicine and oral health studies due to their antibacterial properties and ecologically sustainable manufacturing.

CALLUS INDUCTION OF Sonchus arvensis L. AND ITS ANTIPLASMODIAL ACTIVITY

Background:

Malaria is a global health problem that requires urgent need for new drugs. Tempuyung (Sonchus arvensis L.) possesses many potential medicinal compounds. As the plant is originally found wild, it is important to reproduce its secondary metabolites by tissue culture. The objectives of this study were to look for effective methods to induce callus from leaf explants of Sonchus arvensis L. and to test its in vitro antiplasmodial activity.

Materials and Methods:

The leaves and petioles of the plant were cultured on Murashige and Skoog (MS) solid medium supplemented with indole acetic-3-acid (IAA), indole-3-butyric acid (IBA), naphthalene acetic acid (NAA), 2,4-dichlorophenoxyacetic acid (2,4-D) and benzyl amino purine (BAP), in light and dark incubations. The best results obtained from callus induction were then treated by with several concentrations of sucrose (1- 5%). The best results from callus induction were then extracted with methanol for antiplasmodial test by Trager and Jensen’s method. It was also tested against 3D7 strain of Plasmodium falciparum.

Results:

The combination of 1mg/L 2,4-D and 0.5 mg/L BAP in dark incubation was the best treatment for callus induction of tempuyung. It produced the best quality of callus and the shortest period for callusing. Sucrose treatment had various effects on leaves callusing, but had no effect on petioles callusing, whereby 4% sucrose was the best treatment for leaves callusing in dark incubation. The methanol extract of the best callus had anti-plasmodial activity with IC₅₀=0.343 µg/mL.

Conclusion:

Methanol extract of tempuyung callus shows potential as an antimalarial drug but more studies would be required.

Green alga Ulva pertusa--a new source of bioactive compounds with antialgal activity

We tested the effects of solvent fractions (FA, FB, FC, and FD), which partitioned by liquid-liquid extraction from the methanol extract of Ulva pertusa, on the growth of red tide microalgae (Karenia mikimitoi, Skeletonema costatum, Alexandrium tamarense, Heterosigma akashiwo, Prorocentrum donghaiense), and FA, FB, and FC exhibited significantly antialgal activity. The chemical constituent analysis showed the existence of bioactive compounds such as phenols and alkaloids. Further, four solvent fractions were applied to silica gel column and repeated preparative TLC to produce 13 samples and their purity qualified as thin-layer chromatographic grade. Among these purified samples, FA111, FB411, FC411, FD111, and FD211 exhibited stronger antialgal activity. Furthermore, their functional groups were analyzed by colorimetric methods and UV spectra data. FD111 and FD211 were temptatively identified as alkaloids; the others were initially identified as phenolic acids. This is a preliminary study and the structure identification of these purified samples requires further investigation. While concentration of these purified samples in this algae was very small, they showed excellent effects against red tide microalgae.

Assessment of dual life stage antiplasmodial activity of british seaweeds

Terrestrial plants have proven to be a prolific producer of clinically effective antimalarial drugs, but the antimalarial potential of seaweeds has been little explored. The main aim of this study was to assess the in vitro chemotherapeutical and prophylactic potential of the extracts of twenty-three seaweeds collected from the south coast of England against blood stage (BS) and liver stage (LS) Plasmodium parasites. The majority (14) of the extracts were active against BS of P. falciparum, with brown seaweeds Cystoseira tamariscifolia, C. baccata and the green seaweed Ulva lactuca being the most active (IC(50)s around 3 μg/mL). The extracts generally had high selectivity indices (>10). Eight seaweed extracts inhibited the growth of LS parasites of P. berghei without any obvious effect on the viability of the human hepatoma (Huh7) cells, and the highest potential was exerted by U. lactuca and red seaweeds Ceramium virgatum and Halopitys incurvus (IC50 values 14.9 to 28.8 μg/mL). The LS-active extracts inhibited one or more key enzymes of the malarial type-II fatty acid biosynthesis (FAS-II) pathway, a drug target specific for LS. Except for the red seaweed Halopitys incurvus, all LS-active extracts showed dual activity versus both malarial intracellular stage parasites. This is the first report of LS antiplasmodial activity and dual stage inhibitory potential of seaweeds.