Ethnomedicinal plants used for the treatment of neurodegenerative diseases in Himachal Pradesh, India in Western Himalaya

ETHNOPHARMACOLOGICAL RELEVANCE

Medicinal plants are considered as a healthcare resource and widely used by rural people in their traditional medicine system for curing neurodegenerative diseases. Neurodegenerative diseases refer to incurable and debilitating conditions that result in progressive degeneration/death of nerve cells or neurons in the human brain. This review is mainly focused on the usage of different ethnomedicinal plants in the treatment of different neurodegenerative diseases in Himachal Pradesh. Study reveals total of 73 ethnomedicinal plants, which are used for treating different neurological disorders in different areas of Himachal Pradesh. The data is compiled from the different sources that described the detailed information of plants in tabular form and highlights the significance of different phytochemicals on neuroprotective function. The present study also provides the scientific data and clinical (in-vivo and in-vitro) studies in support of ethnomedicinal use.

AIM OF THE STUDY

This review aims to provide information of ethnomedicinal plants which are used for the treatment of neurodegenerative diseases in Himachal Pradesh.

MATERIALS AND METHODS

Information on the use of ethnomedicinal plants to treat various neurological disorders has been gathered from a variety of sources, including various types of literature, books, and relevant publications in Google Scholar, Research Gate, Science Direct, Scopus, and Pub Med, among others. The collected data is tabulated, including the botanical names of plants, mode of use and the disease for which it is used for curing, etc. RESULTS: There are 73 ethnomedicinal plants that are used to cure various neurological disorders, with the most plants being used to treat epilepsy problem in Himachal Pradesh.

CONCLUSION

Numerous phytochemicals and extracts from diverse plants were found to have a protective effect against neurodegenerative diseases. Antioxidant activity is known to exist in a variety of herbal plants. The most common bioactive antioxidant chemicals having their significant impacts include flavonoids, flavones, coumarins, lignans, isoflavones, catechins, anthocyanins, and isocatechins.

The prevalence, mechanism of action, and toxicity of Nigerian psychoactive plants

Cannabis sativa, Datura stramonium, Nicotiana tabacum, and Carica papaya are plants that naturally grow in Nigeria. They are reportedly rich in neuroactive compounds that are capable of reacting with the nervous system to elicit psychoactive and/or toxic effects that deter predators. However, despite the toxicological potential of these plants, their recreational use is on the rise due to the psychoactivity they proffer and prevalence in Nigeria. The aim of the present study is to evaluate the plants' recreational use, mechanism of actions and toxicities. Relevant published documents on psychoactive plants in Nigeria were obtained from Web of Science between 2002 and 2020. Non-English documents, documents not in Science Citation Index Expanded and Google Scholar were removed while 1186 documents were reviewed. Results showed that the plants are recreationally used in Nigeria with a higher prevalence than the global frequency. They are very addictive and lead to dependence. The plants were also observed to elicit different mechanism of action, though the activation of monoaminergic neurotransmission system was common to all. Regrettably, the plants could be toxic when ingested under non-medical conditions. Conclusively, these plants are addictive with potential toxic effects. Therefore, control of the recreational use of these plants should be revamped and overhauled.

Analysing Curcuma caesia fractions and essential oil for neuroprotective potential against anxiety, depression, and amnesia

Scientific pieces of evidence support the pharmacological activity of Curcuma caesia for its antidepressant, analgesic, anticonvulsant and antioxidant effect. Here, we evaluate the bioactivity of essential oil and the various polarity-based solvent partitioned fractions obtained from Curcuma caesia for anti-amnesia, anxiolytic and antidepressant activities using Elevated plus maze and Morris water maze models. The cold maceration technique using methanol was adopted for extraction from dried powdered rhizomes and essential oil was extracted by hydrodistillation method. Partitioning of the methanolic extract based on solvent polarity by hexane, ethyl acetate, and methanol was continued, followed by column chromatography of the ethyl acetate fraction. Suspensions were prepared for fractions (dissolved in distilled water) and essential oil (dissolved in tween 20) at 200 mg/kg and 400 mg/kg after acute toxicity study and were orally administered to Wistar albino female rats after the orientation of hypoxia by sodium nitrite (50 mg/kg) and amnesia by scopolamine (1 mg/kg). Behavioural observations, biochemical and histopathological examinations were carried out for all the treated groups. Diazepam (12 mg/kg) and galantamine (3 mg/kg) were used as standard drugs for this study against hypoxia and amnesia. Data acquired from behavioural, biochemical (acetylcholinesterase, myeloperoxidase, superoxide dismutase, reduced glutathione, catalase) and histopathological studies have illustrated that fraction II acquires highly significant memory-enhancing, anxiolytic and antidepressant effects. Rest fractions (I and III) and essential oil showed moderate efficacy. In prospects, identification of active molecules from the most active fraction (fraction II) and further studies on a molecular basis would substantiate its specific mechanism of neuroprotective action.

Alkaloid extracts from Jimson weed (Datura stramonium L.) modulate purinergic enzymes in rat brain

Although some findings have reported the medicinal properties of Jimson weed (Datura stramonium L.), there exist some serious neurological effects such as hallucination, loss of memory and anxiety, which has been reported in folklore. Consequently, the modulatory effect of alkaloid extracts from leaf and fruit of Jimson weed on critical enzymes of the purinergic [ecto-nucleoside triphosphate diphosphohydrolase (E-NTPDase), ecto-5'-nucleotidase (E-NTDase), alkaline phosphatase (ALP) and Na⁺/K⁺ ATPase] system of neurotransmission was the focus of this study. Alkaloid extracts were prepared by solvent extraction method and their interaction with the activities of these enzymes were assessed (in vitro) in rat brain tissue homogenate and in vivo in rats administered 100 and 200mg/kg body weight (p.o) of the extracts for thirty days, while administration of single dose (1mg/kg body weight; i.p.) of scopolamine served as the positive control. The extracts were also investigated for their Fe²⁺ and Cu²⁺ chelating abilities and GC-MS characterization of the extracts was also carried out. The results revealed that the extracts inhibited activates of E-NTPDase, E-NTDase and ALP in a concentration dependent manner, while stimulating the activity of Na⁺/K⁺ ATPase (in vitro). Both extracts also exhibited Fe²⁺ and Cu²⁺ chelating abilities. Considering the EC₅₀ values, the fruit extract had significantly higher (P<0.05) modulatory effect on the enzymes' activity as well as metal chelating abilities, compared to the leaf extract; however, there was no significant difference (P>0.05) in both extracts' inhibitory effects on E-NTDase. The in vivo study revealed reduction in the activities of ENTPDase, E-NTDase, and Na⁺/K⁺ ATPase in the extract-administered rat groups compared to the control group, while an elevation in ALP activity was observed in the extract-administered rat groups compared to the control group. GC-MS characterization revealed the presence of atropine, scopolamine, amphetamine, 3-methyoxyamphetamine, 3-ethoxyamhetamine cathine, spermine, phenlyephirine and 3-piperidinemethanol, among others in the extracts. Hence, alterations of activities of critical enzymes of purinergic signaling (in vitro and in vivo) by alkaloid extracts from leaf and fruit of Jimson weed suggest one of the mechanisms behind its neurological effects as reported in folklore.