Characterization, molecular identification, and antimicrobial activity of lactic acid bacteria isolated from selected fermented foods and beverages in Malaysia.

The present work investigated the profile and biodiversity of lactic acid bacteria (LAB) isolated from selected manufactured and homemade fermented foods in Malaysia. A total of 55 LAB were isolated from 20 samples, and identified based on the sequencing of 16S rRNA gene. The LAB isolates were identified as Lacticaseibacillus rhamnosus (34.5%), Lactiplantibacillus plantarum (20%), Limosilactobacillus fermentum (20%), Lacticaseibacillus paracasei (12.7%), Lacticaseibacillus casei (3.6%), Lactobacillus sp. (1.8%), Enterococcus faecalis (3.6%), Enterococcus faecium (1.8%), and Enterococcus durans (1.8%). Majority (94%) of the LAB isolates exhibited broad-spectrum antimicrobial activity against selected foodborne pathogens, and four isolates (L. fermentum SC1001, L. paracasei K2003, and L. rhamnosus KF1002 and MK2003) could produce bacteriocin-like inhibitory substance (BLIS). Lacticaseibacillus paracasei M1001 (homemade mozzarella) exhibited high-temperature tolerance and acid resistance, was homofermentative, and generated good antimicrobial activity, which strongly implied its potential for industrial applications. The present work results would potentially widen our knowledge of LAB diversity in Malaysian fermented foods and provide a potential for their applications in the food industry or other purposes.

Free Radical Scavenging, Anti-Infectious, and Toxicity Activities from Stenochlaena palustris (Burm.f.) Bedd. Extracts.

Stenochlaena palustris (Burm.f.) Bedd. (Blechnaceae) or Kelakai is a traditional medicinal plant found in the Indonesian islands of Borneo and Sumatra. It has been used to treat wound healing, infection, and diabetes. This study looked into the free radical scavenging activity, antiplasmodial activity, toxicity, and antibacterial activity against pathogenic bacteria. The species' aerial part was extracted with methanol, followed by a liquid-liquid extraction against (n-hexane, dichloromethane, and ethyl acetate). The extracts' free radical scavenging activities were determined using DPPH and NO radicals. The antiplasmodial and toxicity assays were conducted using two Plasmodium falciparum strains (3D7 and W2) and the brine shrimp lethality test. In addition, antibacterial activity was determined using the well diffusion method. The results revealed that ethyl acetate depicted potential activities toward the assay. The ethyl acetate showed potential free radical scavenging activities with an IC50 value of 51.63 ± 0.46 µg/mL (DPPH) and 60.03 ± 0.65 µg/mL (NO). The antiplasmodial activities showed that the ethyl acetate had potential activities among the extracts with an IC50 value of 11.06 ± 0.45 µg/mL. However, all the extracts demonstrated nontoxic toward Artemia salina with LC50 > 1000 µg/mL. Furthermore, the ethyl acetate demonstrated intermediate susceptibility against B. cereus ATCC 10876, V. parahaemolyticus ATCC 17802, L. monocytogenes ATCC 7644, and S. Typhimurium ATCC 14028 at a concentration of 500 µg/disc. According to these findings, the ethyl acetate extract of S. palustris (Burm.f.) Bedd is a promising source of natural antioxidants and antiplasmodial agents.

Cytotoxicity and Antiplasmodial Properties of Different Hylocereus polyrhizus Peel Extracts.

BACKGROUND Dragon fruit (Hylocereus polyrhizus) is one of the most common fruits in tropical countries, including Indonesia. The unique deep purple-colored pulp of the fruit is eaten whole and consumed as juice. However, the inedible thick peel is wasted, causing environmental issues. In this study, the toxic, cytotoxic, and antiplasmodium activity from various extract of H. polyrhizus peels were examined. MATERIAL AND METHODS We evaluated the cytotoxicity and antiplasmodial properties of the various peel extracts by using different organic solvents.The extraction of the peels was conducted using maceration to obtain pigment, n-hexane, dichloromethane, and ethyl acetate extracts. The toxicity of the extract was assessed using the brine shrimp lethality test, followed by WST assay to test in vitro cytotoxic properties and in vitro antiplasmodial properties in 2 Plasmodium falciparum strains (3D7 and W2). RESULTS The n-hexane, dichloromethane, and ethyl acetate extracts depicted various levels of activity, whereas the pigment extract did not show any activities. However, dichloromethane demonstrated a high toxicity level with LC50 of 10.32±0.13 µg/mL and a weak cytotoxic level against SK-OV-3 cell lines (IC50 of 560.86±0.63 µg/mL). Moreover, the dichloromethane and n-hexane extracts showed high and promising antiplasmodial activity with IC50 2.13±0.42 and 6.51±0.49 µg/mL, respectively. CONCLUSIONS The dichloromethane extract demonstrated high antiplasmodial activity. Our observations have elucidated the cytotoxic and antiplasmodial activity of the peel of dragon fruits and can be used as a foundation for further research into the isolation and bioactivity of secondary metabolites.