Advances in sample preparation methods for pesticide residue analysis in medicinal plants: A focus on Nepal.

Medicinal plant safety is a rising challenge worldwide due to the continued overuse of pesticides to their maximum residue limits. Due to the high demand for medicinal plants, their production is being increased and sometimes protected by pesticide use. The analysis of these residues requires robust analytical methods to ensure the safety and quality of medicinal plants. Developing effective sample preparation for detecting pesticides is challenging, due to their diverse natures, classes, and physico-chemical characteristics. Hence, existing techniques and strategies are needed to improve the reliability of the results. The review discusses the current state of sample preparation techniques, analytical methods, and instrumental technologies employed in pesticide residue analysis in medicinal plants. It highlights the challenges, limitations, and advancements in the field, providing insights into the analytical strategies used to detect and quantify pesticide residues. Reliable, accessible, affordable, and high-resolution analytical procedures are essential to ensure that pesticide levels in medicinal plants are effectively regulated. By understanding the complexities of pesticide residue analysis in medicinal plants, this review article aims to support the conservation of medicinal plant resources, promote public health, and contribute to the development of sustainable strategies for ensuring the safety and quality of medicinal plants in Nepal. The findings of this review will benefit researchers, policymakers, and stakeholders involved in the conservation of medicinal plant resources and the promotion of public health.

The Influence of Environmental Conditions on Secondary Metabolites in Medicinal Plants: A Literature Review.

Medicinal plants, a source of different phytochemical compounds, are now subjected to a variety of environmental stresses during their growth and development. Different ecologically limiting factors including temperature, carbon dioxide, lighting, ozone, soil water, soil salinity and soil fertility has significant impact on medicinal plants' physiological and biochemical responses, as well as the secondary metabolic process. Secondary metabolites (SMs) are useful for assessing the quality of therapeutic ingredients and nowadays, these are used as important natural derived drugs such as immune suppressant, antibiotics, anti-diabetic, and anti-cancer. Plants have the ability to synthesize a variety of secondary metabolites to cope with the negative effects of stress. Here, we focus on how individual environmental variables influence the accumulation of plant secondary metabolites. A total of 48 articles were found to be relevant to the review topic during our systematic review. The review showed the influence of different environmental variables on SMs production and accumulation is complex suggesting the relationship are not only species-specific but also related to increases and decline in SMs by up to 50 %. Therefore, this review improves our understanding of plant SMs ability to adapt to key environmental factors. This can aid in the efficient and long-term optimization of cultivation techniques under ambient environmental conditions in order to maximize the quality and quantity of SMs in plants.

Sesquiterpene rich essential oil from Nepalese Bael tree (Aegle marmelos (L.) Correa) as potential antiproliferative agent.

Aegle marmelos (L.) Corr. (Rutaceae), also known as Bael tree, is an herbal traditional remedy in the South East Asia. In the present work, the leaf essential oil distilled from a population collected in Nepal was analyzed for the chemical composition by GC-MS showing different phytochemical constituents compared with literature data. The obtained oil was rich in sesquiterpenes, mainly ß-Caryophyllene (26%), whereas monoterpenes, known in literature as the major components, were present in little amounts. Due to richness in sesquiterpenes which are promising as anticancer drugs, the oil was tested against several human tumor cell lines namely pancreatic (PSN-1), colon (LoVo), lung (H157) and ovarian (2008) cells showing IC50 of 5.6 µg/mL, 6.5 µg/mL, 6.7 µg/mL and 2.3 µg/mL, respectively. In vivo distribution of oil was studied with a dose of 41.5 mg/kg in mice allowing the quantification of ß-Caryophyllene, α-Humulene, γ-Muurulene and ar-Curcumene at 30 and 60 min after oral administration. Sesquiterpene were found in higer amount in, liver, kidney and heart whereas lung and blood contained lower levels. The tissue distribution study demonstrated that active sesquiterpenoids of the oil can efficiently reach different organs.