Neurodegeneration leads to the loss of structural and functioning components of neurons over time. Various studies have related neurodegeneration to a number of degenerative disorders. Neurological repercussions of neurodegeneration can have severe impacts on the physical and mental health of patients. In the recent past, various neurodegenerative ailments such as Alzheimer’s and Parkinson’s illnesses have received global consideration owing to their global occurrence. Environmental attributes have been regarded as the main contributors to neural dysfunction-related disorders. The majority of neurological diseases are mainly related to prenatal and postnatal exposure to industrially produced environmental toxins. Some neurotoxic metals, like lead (Pb), aluminium (Al), Mercury (Hg), manganese (Mn), cadmium (Cd), and arsenic (As), and also pesticides and metal-based nanoparticles, have been implicated in Parkinson’s and Alzheimer’s disease. The contaminants are known for their ability to produce senile or amyloid plaques and neurofibrillary tangles (NFTs), which are the key features of these neurological dysfunctions. Besides, solvent exposure is also a significant contributor to neurological diseases. This study recapitulates the role of environmental neurotoxins on neurodegeneration with special emphasis on major neurodegenerative disorders such as Alzheimer’s and Parkinson’s disease.

Skimmia anquetilia is a plant species native to the Western Himalaya region that has tremendous potential for phytochemical activities. This study aimed to identify bioactive compounds and assess the antibacterial activity of S. anquetilia. To determine the major bioactive chemicals in the methanol leaf extract of S. anquetilia, we used a gas chromatography–mass spectrometer (GC-MS). The presence of 35 distinct phytoconstituents was discovered using GC-MS, which could contribute to the therapeutic capabilities of this plant species. The most predominant compound was 2R-acetoxymethyl-1,3,3-trimethyl-4t-(3-methyl-2-buten-1-yl)-1t-cyclohexanol (23.9%). Further, the leaf extract was evaluated for antibacterial activity against Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Salmonella typhi, and Staphylococcus aureus. The extract showed the highest zone of inhibition against E. coli (19 mm) followed by P. aeruginosa (18 mm) and K. Pneumoniae (17 mm) at 160 mg mL−1. The minimum inhibitory concentration (MIC) of methanol extract against the strain of P. aeruginosa (2 mg mL−1) demonstrated significant antibacterial activity. The findings of the present study highlight the potential of S. anquetilia for the development of herbal medicines for the treatment of various pathogenic infections.

The present study aimed to explore the antibacterial activity of various organic root extracts of Skimmia anquetilia N.P. Taylor and Airy Shaw and the identification of major functional groups and phytoconstituents through fourier transform infrared spectrometer (FTIR) and gas chromatography-mass spectrometer (GC-MS). The extracts were evaluated for antibacterial activity against multidrug-resistant (MDR) strains viz., Pseudomonas aeruginosa (MTCC424), Escherichia coli (MTCC739), Klebsiella pneumoniae (MTCC139), Salmonella typhi (MTCC3224), and Staphylococcus aureus (MTCC96). ESKAPE pathogens such as S. aureus, K. pneumoniae, and P. aeruginosa are responsible for a majority of all healthcare acquired infections. The ethyl acetate extract showed the highest zone of inhibition against P. aeruginosa (18 mm) followed by S. aureus (17 mm). The minimum inhibitory concentration (MIC) of ethyl acetate extract against strain of S. aureus (4 mg mL–1) demonstrated therapeutically significant antibacterial activity. The FTIR spectra of root extracts revealed the occurrence of functional characteristic peaks of alcohols, carboxylic acids, aromatic compounds, alkanes, alkenes, and amines that indicates the presence of various metabolites in the extracts. The GC-MS investigation led to the identification of diverse phytoconstituents in each of the extracts with varying concentrations and molecular masses. The highest number of compounds were identified from the methanol extract (112), followed by n-hexane extract (88) and ethyl acetate extract (74). The most predominant compounds were 5, 10-pentadecadien-1-ol, (Z,Z)-(33.94%), n-hexadecanoic acid (13.41%) in n-hexane extract, 5,10-pentadecadien-1-ol, (Z,Z)-(10.48%), 1-hexyl-2-nitrocyclohexane (7.94%) in ethyl acetate extract, and 1-hexyl-2-nitrocyclohexane (15.43%), cis,cis,cis-7,10,13-hexadecatrienal (13.29%) in methanol extract. The results of the present study will create a way for the invention of plant-based medicines for various life-threatening microbial infections using S. anquetilia, which may lead to the development of novel drugs against drug-resistant microbial infections.

Skimmia anquetilia N.P. Taylor and Airy Shaw (Rutaceae) is a perennial, aromatic, gregarious wild ornamental shrub native to the Western Himalaya. The plant is used in the traditional medicinal system to treat copious health conditions like rheumatism, fever, inflammation, headache, influenza, body-ache, clearing of the nose, diabetes, lowering the body temperature, smallpox, wounds, burns, snake, and scorpion bites. Phytochemical and gas chromatography-mass spectrometer (GC-MS) analysis of S. anquetilia showed the presence of alkanes, alkenes, carboxylic acids, fatty acids, and their esters, simple coumarins, terpenes, phenylpropanoid, and so on. These active principles exhibit a wide array of pharmacological effects, including anti-inflammatory, antioxidant, anti-cancerous, anti-feedant, and antibacterial properties. Most pharmacological studies were based on the essential oil and the crude extracts of the plant and the bioactive compounds responsible for the bioefficacy have not been well-identified. Further investigations are required to transform the experience-based claims on the use of S. anquetilia in traditional medicine practices into evidence-based information. Detailed in-vitro and in-vivo studies on the mechanisms of action of pure bioactive compounds and more elaborate toxicity studies to ensure plant safety for human use should be conducted. This review recapitulates the current status of its use in the ethnobotany, phytochemistry, and pharmacological activities. It also offers a critical assessment of the plant’s existing information which would help to recuperate its potential as a source for drug development of lead molecules.

Withania somnifera (L.) Dunal belongs to the nightshade family Solanaceae and is commonly known as Ashwagandha. It is pharmacologically a significant medicinal plant of the Indian sub-continent, used in Ayurvedic and indigenous systems of medicine for more than 3,000 years. It is a rich reservoir of pharmaceutically bioactive constituents known as withanolides (a group of 300 naturally occurring C-28 steroidal lactones with an ergostane-based skeleton). Most of the biological activities of W. somnifera have been attributed to two key withanolides, namely, withaferin-A and withanolide-D. In addition, bioactive constituents such as withanosides, sitoindosides, steroidal lactones, and alkaloids are also present with a broad spectrum of therapeutic potential. Several research groups worldwide have discovered various molecular targets of W. somnifera, such as inhibiting the activation of nuclear factor kappa-B and promoting apoptosis of cancer cells. It also enhances dopaminergic D2 receptor activity (relief in Parkinson’s disease). The active principles such as sitoindosides VII-X and withaferin-A possess free radical properties. Withanolide-D increases the radio sensitivity of human cancer cells via inhibiting deoxyribonucleic acid (DNA) damage to non-homologous end-joining repair (NHEJ) pathways. Withanolide-V may serve as a potential inhibitor against the main protease (Mpro) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to combat COVID. The molecular docking studies revealed that the withanolide-A inhibits acetyl-cholinesterase in the brain, which could be a potential drug to treat Alzheimer’s disease. Besides, withanolide-A reduces the expression of the N-methyl-D-aspartate (NMDA) receptor, which is responsible for memory loss in epileptic rats. This review demonstrates that W. somnifera is a rich source of withanolides and other bioactive constituents, which can be used as a safe drug for various chronic diseases due to the minimal side effects in various pre-clinical studies. These results are interesting and signify that more clinical trials should be conducted to prove the efficacy and other potential therapeutic effects in human settings.