#antimicrobial activity

From ancient civilization, spices and herbs have played an important role in the lifestyle of people around the world. As Spices are being used from generation to generation as food additives and traditional medicines, these have been used as study materials to investigate its different bioactive properties and phytochemicals for their potential usage in the pharmaceutical industries. Phytochemicals are the compounds produced by plants, but not directly used for the growth and development rather engaged in protection against environmental and pathogenic stress. Plant materials were collected and water extraction method was applied for the preparation of extracts. After extraction all of the experiments were done according to standard protocols. Our study focused on the screening of the presence of valuable phytochemicals in ten widely used spices in Bangladesh. Among phytochemical screened tannin, glycosides and phenolic compounds are most abundant in all spices. The highest phenolic content was found in Syzygium aromaticum (67.77 µg GAE/ml of extract) and the lowest phenolic content was found in Coriandrum sativum (4.22 µg GAE/ml of extract). Among the spices, Myristica fragrans contained the highest tannin content (78.75 µg TAE/ml Extract) and Elettaria cardamomum contained the lowest tannin content (61 µg TAE/ml Extract). The study also employed the antibacterial activity of the spices extracts. The extracts showed the strongest antibacterial activity against the gram-positive bacteria when compared to the gram-negative bacteria. The highest zone of inhibition for Escherichia coli, Bacillus subtilis, and Salmonella typhi were found 8.31 mm, 10.4 mm and 8.61 mm in Nigella sativa, Elettaria cardamomum and Amomum subulatum respectively, and the lowest zone of inhibition for Escherichia coli, Bacillus subtilis, and Salmonella typhi were found 5.18 mm, 5.36 mm and 5.86 mm in Coriandrum sativum, Coriandrum sativum and Syzygium aromaticum respectively. Thin layer chromatographic (TLC) analysis was also done to check the presence of phyto-constituents. Our study revealed several spots (From 1 to 3) for different samples and their retention factors (Rf) were calculated. It is concluded that, results of these investigations had provided valuable information on further discovery of noble drugs.

The increasing environmental and health concerns associated with synthetic pigments have intensified the search for sustainable and biologically derived alternatives. Actinomycetes are recognized as promising producers of natural pigments; however, pigment production by rare actinomycete genera remains underexplored. In the present study, a pigment-producing actinomycete isolated from mangrove sediment was identified as Pseudonocardia alni based on morphological, biochemical, and 16S rRNA gene sequence analyses (GenBank accession no. PP296388). Pigment production was optimized by evaluating physicochemical parameters including pH, temperature, and salinity. The feasibility of agro-waste substrates for cost-effective pigment production was assessed through solid-state fermentation. Among the tested substrates, tapioca peel supported the highest pigment yield (1.388 ± 0.034), followed by groundnut oil cake and coconut oil cake, with statistically significant differences among substrates (p < 0.05). The extracted pigment exhibited a characteristic visible absorption maximum in UV–Visible spectroscopy, indicating a conjugated chromophore, while FTIR analysis revealed aromatic, hydroxyl, carbonyl, and nitrogen-containing functional groups. The pigment showed broad-spectrum antibacterial activity against selected Gram-positive and Gram-negative pathogens. Overall, the study demonstrates the potential of Pseudonocardia alni as a sustainable source of a bioactive pigment and highlights agro-waste valorization as an effective strategy for eco-friendly pigment production.

The increasing environmental and health concerns associated with synthetic pigments have intensified the search for sustainable and biologically derived alternatives. Actinomycetes are recognized as promising producers of natural pigments; however, pigment production by rare actinomycete genera remains underexplored. In the present study, a pigment-producing actinomycete isolated from mangrove sediment was identified as Pseudonocardia alni based on morphological, biochemical, and 16S rRNA gene sequence analyses (GenBank accession no. PP296388). Pigment production was optimized by evaluating physicochemical parameters including pH, temperature, and salinity. The feasibility of agro-waste substrates for cost-effective pigment production was assessed through solid-state fermentation. Among the tested substrates, tapioca peel supported the highest pigment yield (1.388 ± 0.034), followed by groundnut oil cake and coconut oil cake, with statistically significant differences among substrates (p < 0.05). The extracted pigment exhibited a characteristic visible absorption maximum in UV–Visible spectroscopy, indicating a conjugated chromophore, while FTIR analysis revealed aromatic, hydroxyl, carbonyl, and nitrogen-containing functional groups. The pigment showed broad-spectrum antibacterial activity against selected Gram-positive and Gram-negative pathogens. Overall, the study demonstrates the potential of Pseudonocardia alni as a sustainable source of a bioactive pigment and highlights agro-waste valorization as an effective strategy for eco-friendly pigment production.

Our study focused on the study of the antibacterial and antioxidant properties of citrus essential oils (EO) of Citrus sinensis, Citrus reticulata, Citrus limon and Citrus maxima. The extraction of essential oils from the four citrus species was carried out using the hydrodistillation method using an extraction device adapted to the Laboratory. The antioxidant activity of different citrus fruits has been evaluated by neutralizing the DPPH radical. The following yields of EO were obtained: 0.74% and 0.80%, respectively for the EO of the sweet orange from Morocco and the wild orange from Cameroon; 0.2%, for EO of Mandarin; 0.18% and 0.13% respectively for the EO of lemon and Grapefruit. Microscopic observations revealed the presence in fermented milk, apart from lactic acid bacteria of the presence of Micrococcus spp Gram + bacteria from the family of Micrococcaceae been used for antibacterial testing. The results showed that HE has antibacterial activity with regard to the diameters of the halos. It appears that all citrus fruits have different activities. The EO of C. lemon has the best antioxidant activity followed by that of the Wild Orange with a diameter of the inhibition zone of 13 ± 1.41 and 9.5 ± 1.41mm respectively.