Pimarane Diterpenoids from Aerial Parts of Lycopus lucidus and Their Antimicrobial Activity

Evaluation of Minimum Inhibitory Concentration of Heavy Metals Contained in Packaging Material Digest on Prominent Gut Microbiota

Several scientific investigations have revealed that the leaching of metals from packaging material into the packed food is an unavoidable process. Hence, this study is aimed at investigating the effect of leached heavy metals from food packing materials on normal human gut flora. We analysed the effect of vanadium, arsenic, cadmium, and mercury present in digested packaging materials (DPM) on standard strains of Escherichia coli ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC 70063, and Enterococcus faecalis ATCC 29212. The minimum inhibitory concentration (MIC) of laboratory-grade heavy metal salts and heavy metals present in DPM was determined by the agar dilution method. For all four bacteria, the MIC of cadmium and arsenic in the DPM was 7 μg/ml and 1.6 μg/ml, respectively. The MIC of mercury in DPM was 1.6 μg/ml for E. coli, K. pneumoniae, and E. faecalis and 1.4 μg/ml for P. aeruginosa. MIC of vanadium for E. coli, P. aeruginosa, and E. faecalis was 2.2 μg/ml, and for K. pneumoniae was 2.0 μg/ml. The difference in MICs of heavy metals in DPMs and heavy metal salts was not statistically significant. MICs were within CODEX-specified permissible levels. Though heavy metals in packaging material have not shown a deleterious effect on representative human gut flora, there is scope to study their effect on the gut microbiome. Thus, understanding the risk of heavy metal ingestion through unknown sources and avoiding any possible ingestion is crucial to preventing chronic diseases.

Antibacterial and Antioxidant Activities of Prinsepia utilis Royle Leaf and Seed Extracts

Our study was designed to screen the antibacterial potency of Princepia utilis leaf and seed extract and to measure their antioxidant effects, total phenol content, total flavonoid content, and total carbohydrate content. Collected samples were extracted by cold maceration. Hexane, ethyl acetate, methanol, and distilled water were used as extraction solvents. In the disc diffusion method, P. utilis ethyl acetate leaf extract was most prominent against Staphylococcus epidermis with a zone of inhibition (ZOI) of 13.83 mm. Similarly, methanolic leaf extract was most prominent against Staphylococcus aureus (ZOI-12.33 mm). Furthermore, the methanolic seed extract was most sensitive against Klebsiella pneumoniaee (ZOI-11.66 mm) Escherichia coli (ZOI-9.0 mm). The lowest minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 0.5 mg/mL and 0.6 mg/mL, respectively, were shown by ethyl acetate leaf extract against S. epidermis. Similarly, the highest values of MIC and MBC, i.e., 20.8 mg/mL and 33.3 mg/mL, respectively, were shown by hexane leaf extract against S. epidermidis. On the other hand, evaluation of antioxidant capacity revealed that ethyl acetate leaf extract showed the maximum antioxidant effect (IC₅₀: 66.69 μg/mL). The total flavonoid contents of different extracts were measured in the range of 37 ± 0.74 μg QE/mg dry extract weight (methanolic seed extract) to 321.84 ± 4.82 μg QE/mg dry extract weight (hexane seed extract). Likewise, the total polyphenol content ranged from the hexane leaf extract (17.33 ± 0.642 μg GAE/mg dry extract weight) to ethyl acetate leaf extract (62.56 ± 1.284 μg GAE/mg dry extract weight). We found a variation in total carbohydrate content in the range of 23.55 ± 1.125 μg glucose/mg dry extract weight (hexane leaf extract) to 96.63 ± 2.253 μg glucose/mg dry extract weight (aqueous leaf extract). Overall, this study revealed that leaf and seed extract of P. utilis exhibited noteworthy antibacterial effects against diverse pathogenic microorganisms.

Study of Antibacterial Activity of Root Bark, Leaves, and Pericarp Extracts of Diploknema butyracea and Evaluation of Prospective Antioxidant Activity

This study was aimed to determine the antibacterial activity of root bark, leaves, and pericarp extract of Diploknema butyracea and to evaluate the prospective antioxidant activity, total flavonoid, polyphenol, and carbohydrate content. The plant parts were collected and extracted by cold maceration, using hexane, ethyl acetate, methanol, and distilled water. Phytochemical screening of different samples of D. butyracea in different solvents revealed the presence of varied extent of alkaloid, saponin, terpenoid, anthraquinones, tannin, cardiac glycoside, flavonoid, carbohydrate, polyphenol, protein and amino acid, resin, and phytosterol. Our study showed that methanolic root bark extract exhibited the potent antimicrobial activity against Staphylococcus aureus, Staphylococcus epidermidis, and Klebsiella pneumonia with an average zone of inhibition of 17.33 mm, 14.33 mm, and 13.0 mm, respectively. Surprisingly, all of the extracts were insensitive to Escherichia coli. The lowest minimum bactericidal concentration (MBC), 4.6 mg/ml, was observed with the aqueous pericarp extract against S. epidermidis and the highest was of 50 mg/ml shown by ethyl acetate pericarp against K. pneumonia. Our results showed that both the polar and nonpolar components present in the different parts of D. butyracea exhibit prominent antibacterial activities against different bacterial strains. The in vitro 2,2′-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity showed that the methanol extract of root barks displayed the most potent antioxidant activity (IC50 : 6.1 µg/ml). The total polyphenol content of the plant part extracts was observed between 19.48 ± 0.23 and 123.48 ± 1.84 µg gallic acid equivalent/mg of dry extract weight. Likewise, flavonoid content ranged from 40.63 ± 1.28 µg to 889.72 ± 3.40 μg quercetin equivalent/mg of dry extract weight and total carbohydrate content ranged from 11.92 ± 0.60 µg to 174.72 ± 0.60 µg glucose equivalent per/mg dry extract weight. Overall, our study showed that the root bark, pericarp, and leaves extract of D. butyracea evinced prominent antibacterial properties against various pathogenic bacterial strains.