Quantification of macro, micro and trace elements, and antimicrobial activity of medicinal herbs and their products

The study describes the content of macro, micro, and trace essential and toxic elements in thirteen medicinal herbs and their products including Acorus calamus, Blepharis edulis, Caesalpinia bonducella, Curculigo orchioides, Helicteres isora, Holarrhena pubescens, Pastinaca sativa, Pistacia integerrima, Quercus infectoria, Rauwolfia serpentina, Saussurea lappa, Teucrium stocksianum, and Xanthium strumarium available in the local markets of Pakistan. The elemental content were analyzed with the techniques of inductively coupled plasma (ICP) optical emission spectroscopy (OES) and ICP-mass spectrometry (MS). Furthermore, their antibacterial and antifungal activities were evaluated against the selected microbial pathogens including Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis and Escherichia coli, Candida albicans, Candida krusei, Aspergillus flavus, and Trichophyton mentagrophytes. Among macro elements, K and Ca showed the highest content, micro elements were in the order of Rb85/ Sr87 > Zn64/Cu63 > Ni60, and among essential trace elements, the content of Cr52/Cr53 and Co59 were high. The content of the analyzed toxic elements were lower than the permissible standard values. The antimicrobial activities against the subject strains were significant with inhibition zones of 7.0-19.0 mm in disc diffusion procedure, and 62.5–1000 µg/mL in minimum inhibitory concentration method. Hence, the presence of nutritional elements at appreciable concentrations, toxic elements within permissible ranges, and significant antimicrobial potential assume the subject herbs as promising nutritional and therapeutic remedies.