Narjatamolide, an Unusual Homoguaiane Sesquiterpene Lactone from Nardostachys jatamansi

Ethnopharmacologically important highly subsidized Indian medicinal plants: Systematic review on their traditional uses, phytochemistry, pharmacology, quality control, conservation status and future prospective

ETHNOPHARMACOLOGICAL RELEVANCE

India has an extensive reservoir of traditional wisdom and a diverse range of medicinal plants that enrich its heritage. Plants have actively been used for healthcare practices globally since the time immemorial. Medicinal uses of plants have been well recognized in India, evident from plant species documented in different traditional medicinal systems such as Ayurveda (1400-1800 species), Siddha (500-900 species), Unani (400-700 species), Homeopathy (about 372 species), and Sowa-Rigpa (about 250 species), etc. AIM OF THE STUDY: The primary purpose of this review is to provide systematic updated information on thirteen medicinal plants prioritized by the Indian government (providing75 % subsidy on cultivation cost) based on the availability and market demand of these plants. Updated information regarding the traditional uses, phytochemistry, pharmacology, quality control, and conservation status of these plants will help in understanding their pharmacological and commercial importance. This will also help in developing new strategies for their conservation.

MATERIAL AND METHODS

Online databases such as SciFinder, Web of Science, Pubmed, and Google Scholar were used to collect the electronically available literature on targeted thirteen plants. Also, different Indian government official websites such as AYUSH (https://www.ayush.gov.in); NMPB (National Medicinal Plants Board) (https://nmpb.nic.in); e.charak (https://echarak.in) were used for collecting information related to the amount of subsidy, trade and price related information of these plants.

RESULTS

To promote medicinal plant cultivation, the Indian government provides subsidies for cultivating some traditionally important medicinal plants. These plants are divided into three categories according to the subsidy provided to farmers, i.e., 30%, 50%, and 75% of the cost of cultivation. Thirteen medicinal plants which are provided 75% subsidy are Aconitum ferox Wall., Aconitum heterophyllum Wall., Aquilaria agallocha Roxb., Berberis aristata DC., Commiphora wightii (Arn.) Bhandari, Nardostachys jatamansi (D.Don) DC., Oroxylum indicum (L.) Benth. ex Kurz, Picrorhiza kurroa Royle ex Benth., Podophyllum hexandrum Royle, Pterocarpus santalinus L.f., Santalum Album L., Saussurea costus (Falc.) Lipsch., and Swertia chirayita (Roxb.) H.Karst. The literature survey reveals the enormous traditional medicinal importance, wide geographical distribution, diverse range of natural products, and broad spectrum of pharmacological activities of these plants.

CONCLUSION

A comprehensive literature survey revealed that although remarkable progress has been made in isolation, bioactivity evaluation, quality assessment, and conservation, there is still a lot of scope for further scientific interventions. Scientific validation of traditionally claimed medicinal potential is lacking for various bioactivities. Some of the bioactivities are performed just on extracts/fractions, so there is a need for proper phytochemical studies to identify active constituents responsible for the specific bioactivity. Further, quality assessment methods using both targeted and non-targeted tools are required to evaluate the quality of these highly-priced medicinal plants and their adulterants. Ultimately, to encourage the cultivation of these endangered medicinal plant species, it is imperative to implement proper legislation and employ in-situ and ex-situ conservation tools.

Sesquiterpene coumarins from Ferula sinkiangensis and their anti-pancreatic cancer effects

Eight previously unreported sesquiterpene coumarins, namely (+)- and (-)-ferulasinkian A (1), (-)-fukanefuromarin M (2), (±)-ferulasinkian C (3), (±)-ferulasinkian D (4), ferulasinkian E (5), ferulasinkian F (7), and ferulasinkian G (8), together with two known compounds, (+)-fukanefuromarin M (2) and 7-hydroxyferprenin (6), have been isolated from the roots of Ferula sinkiangensis (Umbelliferae). The structures of all compounds were elucidated by spectroscopic analysis, along with ECD calculations and optical rotation calculations. Compounds 1-6 are dimers consisting of a chain sesquiterpene and a coumarin with an oxygen-containing six-membered ring connected from coumarin C-3 and C-4. Currently, there are only seven such structures reported in the genus Ferula, and their absolute configurations have not yet been determined. Compounds 7-8 are sesquiterpene coumarin derivatives with a chain sesquiterpene connected with coumarin C-4. In the present study, the chiral separation of compounds (±)-1 and (±)-2 was successfully carried out, and the absolute configurations of compounds (±)-1, (±)-2, 5, 7 and 8 were determined. The isolates were evaluated for their cytotoxic activity against human pancreatic cancer cell lines including CFPAC-1, PANC-1, CAPAN-2 and SW 1990. Compounds (+)-1, (-)-1 and 7 exhibited potent cytotoxicity against pancreatic cancer cells with IC50 values ranging from 4.57 ± 0.94 to 14.01 ± 1.03 μM. Furthermore, the primary mechanistic study of (-)-1 demonstrated that it could induce apoptosis in CFPAC-1 cells.

Survey of natural products reported by Asian research groups in 2021

The new natural products reported in 2021 in peer-reviewed articles in journals with good reputations were reviewed and analyzed. The advances made by Asian research groups in the field of natural products chemistry in 2021 were summarized. Compounds with unique structural features and/or promising bioactivities originating from Asian natural sources were discussed based on their structural classification.

Terpenoids from Nardostachys jatamansi and their cytotoxic activity against human pancreatic cancer cell lines

Five previously unreported terpenoids, together with fifteen known analogs, were isolated from a methanol extract of the roots and rhizomes of Nardostachys jatamansi. Their structures, including absolute configurations, were elucidated by spectroscopic data and electronic circular dichroism (ECD) spectra analyses, as well as single-crystal X-ray diffraction for crystalline compounds. Structurally, (4R,5S,6S,7R)-1(10)-aristolane-8,9-diacid is a novel 8,9-dicarboxylic acid derivative of aristolane-type sesquiterpenoid. (4R,6S,7R,10S)-10-Hydroxyguaia-1(5)-6,7-epoxy-2-one is an undescribed analogue of nardoguaianone K, with a rare 6,7-epoxide group. (4R,5R,6R,8R)-1(10)-Isonardosinone-8-ol-9-one-7,11-lactone is an isonardosinane-type sesquiterpene bearing a γ-lactone ring. Dinardokanshone F is a rare example of a sesquiterpene dimer from N. jatamansi connected by an oxo bridge. The isolates were evaluated for their cytotoxic activity against four human pancreatic cancer cell lines (CFPAC-1, PANC-1, CAPAN-2 and SW1990). Compound epoxynardosinone exhibited significant cytotoxicity against CAPAN-2 cell lines with IC₅₀ value of 2.60 ± 1.85 μM. 1-Hydroxylaristolone displayed comparable cytotoxicity on CFPAC-1 cell lines (IC₅₀ 1.12 ± 1.19 μM), compared to Taxol (IC₅₀ 0.32 ± 0.13 μM). 1-Hydroxylaristolone, 1(10)-aristolane-9β-ol, 1(10)-aristolen-2-one, alpinenone, valtrate isovaleroyloxyhydrine and nardostachin displayed stronger cytotoxicity against PANC-1 cell lines with IC₅₀ values ranging from 0.01 ± 0.01 to 6.50 ± 1.10 μM. 1(10)-Aristolane-9β-ol, 10-hydroxyguaia-1(5)-6,7-epoxy-2-one, nardoguaianone K, nardonoxide, epoxynardosinone, 1(10)-isonardosinone-8-ol-9-one-7,11-lactone, valtrate isovaleroyloxyhydrine and nardostachin showed remarkable cytotoxicity against SW1990 cell lines with IC₅₀ values ranging from 0.07 ± 0.05 to 4.82 ± 6.96 μM. Furthermore, the primary mechanistic study of nardostachin demonstrated that it induced cell apoptosis via the mitochondria-dependent pathway, and induced SW1900 cell arrest at G2/M phase.

A Coumarin-donepezil Hybrid as a Blood-brain Barrier Permeable Dual Cholinesterase Inhibitor: Isolation, Synthetic Modifications and Biological Evaluation of Natural Coumarins

Plants have immensely contributed to the drug discovery for neurodegenerative diseases. Herein, we undertook the phytochemical investigation of Nardostachys jatamansi (D.Don) DC. rhizomes followed by semisynthetic modifications to discover cholinesterase (ChE) and beta-site amyloid precursor protein cleaving enzyme 1 (BACE-1) inhibitors. The 8-acetyl-7-hydroxycoumarin isolated from the bioactive extract moderately inhibits acetylcholinesterase (AChE) and BACE-1 with IC50 values of 22.1 and 17.7 μM, respectively. The semisynthetic trifluoromethyl substituted coumarin chalcone display a 5-fold improvement in BACE-1 inhibition (IC50 3.3 μM). Another semisynthetic derivative, a coumarin-donepezil hybrid, exhibits dual inhibition of both ChEs with IC50 values of 1.22 and 3.09 μM, respectively. Molecular modeling and enzyme kinetics revealed that the coumarin-donepezil hybrid is a non-competitive inhibitor of AChE. It crosses the blood-brain barrier and also inhibits Aβ self-aggregation. The results presented herein warrant a detailed investigation of the coumarin-donepezil hybrid in preclinical models of Alzheimer's disease.

Three Unusual Sesquiterpenes with Distinctive Ring Skeletons from Daphne penicillata Uncovered by Molecular Networking Strategies

Daphnenoids A-C (1-3), three unusual sesquiterpenes with distinctive ring skeletons, together with a biogenetically related daphnenoid D (4) were obtained from the herb of Daphne penicillata by molecular networking strategies. Daphnenoid A (1) possesses a unique caged tetracyclo [5.3.2.0¹,⁶.0⁴,¹¹] dodecane scaffold by unexpected cyclizations of C-1/C-11 and C-2/C-14. Daphnenoids B and C (2 and 3) were the first discovered natural sesquiterpenes with unique 5/5 spirocyclic systems in nature. Their structures were determined by NMR spectroscopic analysis, computer-assisted structure elucidation methods, quantum chemical calculations, and X-ray diffraction. A hypothetical biogenetic pathway begins with typical guaiane sesquiterpene (a), including a key intermediate (4) was proposed. Daphnenoids B and C (2 and 3) exhibited potential inhibitory activities on the production of NO against LPS-induced BV2 microglial cells.

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