Phytochemistry and pharmacology of Celastrus paniculatus Wild.: a nootropic drug

OBJECTIVES

Celastrus paniculatus Wild is an evergreen climbing shrub. The plant is of great significance in the traditional Indian System of Medicine, such as Ayurveda, Unani, and Siddha. The seeds and their oil are extensively used to treat neurological disorders such as cognitive dysfunction, paralysis, epilepsy, insomnia, and other ailments like rheumatism, arthritis, sciatica, and leprosy. This paper aims to highlight the nootropic activity of C. paniculatus and explore its phytochemistry, traditional uses, and other pharmacological activities.

METHODS

All available information concerning C. paniculatus has been searched in the internationally accepted scientific databases, including PubMed, ScienceDirect, Scopus, and Google Scholar. Additional knowledge was gathered from the classical Textbooks and Unani Pharmacopoeia.

RESULTS

C. paniculatus is a rich source of several secondary metabolites, such as β-Dihydroagarofuranoids sesquiterpenes, alkaloids (Celastrine, Celapanin, Celapagin, and paniculatin), flavonoids, terpenoid (β-amyrin, Lupeol, Pristimerin), sterols (β-sitosterol, campesterol, stigmasterol, α-tocopherol, γ-Tocopherol), fatty acid (palmitic, stearic, oleic, linoleic, linolenic acids) and non-fatty acids (Benzoic acid, Cinnamic acid). The various study shows that the extracts and active constituent of this plant possess potent nootropic activity. Besides nootropic activity, it has also been reported for anti-Alzheimer, anticonvulsant, antidepressant, antioxidant, analgesic, anti-inflammatory, antiarthritic, gastroprotective, anti-psoriatic, wound healing, antibacterial, antimalarial, and several other properties.

CONCLUSIONS

Several in vitro and in vivo trials confirm the conventional use of C. paniculatus in cognitive dysfunction. However, the relations between the possible mechanisms of other activities and traditional uses of the C. paniculatus remain indistinct. Still, pharmacological studies also explored the effects of C. paniculatus, which were not recognized in ancient times, such as cytotoxic, ACE inhibitor, and antidiabetic activities. These discoveries are may be beneficial in the development of the new drug to treat various diseases. It is also confirmed that the β-dihydroagarofuranoids exhibit significant AChE inhibitory, cytotoxic, antibacterial, and insecticidal effects. This versatile medicine is truly a life elixir. Considering the therapeutic importance of the C. paniculatus and the absence of any reported clinical studies, extensive clinical trials are needed to explore its memory enhancing and other activities.

Traditional uses, secondary metabolites, and pharmacology of Celastrus species - a review

ETHNOPHARMACOLOGICAL RELEVANCE

Plants of genus Celastrus (Celastraceae) have been widely used in traditional Chinese medicine (TCM) and Indian medicine to treat cognitive dysfunction, epilepsy, insomnia, rheumatism, gout, and dyspepsia for thousands of years.

AIM OF STUDY

We critically summarized the current evidence on the botanic characterization and distribution, ethnopharmacology, secondary metabolites, pharmacological activities, qualitative and quantitative analysis, and toxicology of Celastrus species to provide perspectives for developing more attractive pharmaceuticals of plant origin.

MATERIALS AND METHODS

The relevant information on Celastrus species was gathered from worldwide accepted scientific databases via electronic search (Web of Science, SciFinder, PubMed, Elsevier, SpringerLink, Wiley Online, China Knowledge Resource Integrated, and Google Scholar). Information was also obtained from the literature and books as well as PhD and MSc dissertations. Plant names were validated by "The Plant List" (www.theplantlist.org).

RESULTS

Comprehensive analysis of the above mentioned databases and other sources confirmed that ethnomedical uses of plants of Celastrus genus had been recorded in China, India, and other countries in Southern Asia. The phytochemical investigation revealed the presence of β-dihydroagarofuranoids, diterpenoids, triterpenoids, tetraterpenes, phenylpropanoids, alkaloids, flavonoids, lignans, and others. The crude extracts and isolated constituents have exhibited a wide range of in vitro and in vivo pharmacological effects, including antitumor, cytotoxic, insecticidal, antimicrobial, anti-rheumatoid arthritis (RA), anti-inflammatory, anti-ageing and antioxidative, and neuroprotective activities.

CONCLUSION

Plants of genus Celastrus have been confirmed to show a strong potential for therapeutic and health-maintaining effects, in light of their long traditional use and the phytochemical and pharmacological studies summarized here. Currently, pharmacological studies of this genus mainly focus on Celastrus paniculatus Willd. and Celastrus orbiculatus Thunb. Therefore, more pharmacological investigations should be implemented to support traditional uses of other medicinal plants of the genus Celastrus. Moreover, studies on the toxicity, bioavailability, and pharmacokinetics, in addition to clinical trials, are indispensable for assessing the safety and efficacy of the secondary metabolites or extracts obtained from plants belonging to this genus.

Identification of a Triterpenoid as a Novel PPARγ Activator Derived from Formosan Plants

Peroxisome proliferator-activated receptor γ (PPARγ), one of the transcription factors that regulate lipid metabolism and energy use in tumor cells, is a viable target for cancer therapy. In our search for potential PPARγ activator, extracts from five Formosan plants were tested. Among them, Momordica charantia L. showed the highest ability to activate PPARγ, which led us to identify its potential constituents. Among the seven compounds isolated from M. charantia, a triterpenoid, 5β,19-epoxy-19-methoxycucurbita-6,23-dien-3β,25-diol (compound 1), was identified as a PPARγ activator with an IC₅₀ of 10 μM in breast cancer MCF-7 cells. Flow cytometric analysis indicated that compound 1 induced G1 cell cycle arrest which might be attributable to the modulation of phosphorylation and expression of numerous key signaling effectors, including cyclin D1, CDK6, and p53. Notably, compound 1 downregulated the expression of histone deacetylase 1, leading to increased histone H3 acetylation. Taken together, these findings suggest that compound 1 may have therapeutic applications in cancer treatment through PPARγ activation. Copyright © 2017 John Wiley & Sons, Ltd.

A Flavone Constituent from Myoporum bontioides Induces M-Phase Cell Cycle Arrest of MCF-7 Breast Cancer Cells

Myoporum bontioides is a traditional medicinal plant in Asia with various biological activities, including anti-inflammatory and anti-bacterial characteristics. To identify the bioactive constituents from M. bontioides, a newly-identified flavone, 3,4'-dimethoxy-3',5,7-trihydroxyflavone (compound 1), along with eight known compounds, were investigated in human MCF-7 breast cancer, SCC4 oral cancer, and THP-1 monocytic leukemia cells. Among these compounds, compound 1 exhibited the strongest antiproliferative activity with half-maximal inhibitory concentration (IC₅₀) values ranging from 3.3 μM (MCF-7) to 8.6 μM (SCC4). Flow cytometric analysis indicated that compound 1 induced G2/M cell cycle arrest in MCF-7 cells. Mechanistic evidence suggests that the G2/M arrest could be attributable to compound 1's modulatory effects on the phosphorylation and expression of numerous key signaling effectors, including cell division cycle 2 (CDC2), CDC25C, and p53. Notably, compound 1 downregulated the expression of histone deacetylase 2 (HDAC2) and HDAC4, leading to increased histone H3 acetylation and p21 upregulation. Together, these findings suggest the translational potential of compound 1 as a breast cancer treatment.

Natural β-Dihydroagarofuran-Type Sesquiterpenoids as Cognition-Enhancing and Neuroprotective Agents from Medicinal Plants of the Genus Celastrus

Alzheimer's disease (AD) is an irreversible, multifaceted, and progressive neurodegenerative disorder. Over the past 30 years, the search for anti-AD drugs has been primarily based on the cholinergic deficiency hypothesis and/or the β-amyloid (Aβ) cascade hypothesis. In this study, we report the identification of 16 new and 38 known β-dihydroagarofuran-type sesquiterpenoids from Celastrus flagellaris and Celastrus angulatus. The β-dihydroagarofuran-type sesquiterpenoids 58, 59, 61, and 63 significantly attenuated scopolamine-induced prolonged escape latency and increased number of errors compared with the control group. At 10 μM, 21 of the 62 tested β-dihydroagarofuran-type sesquiterpenoids rescued Aβ25-35-induced SH-SY5Y cells from viability reduction, which increased the cell viability from 64.6% for the model to more than 74.0%. The majority of the β-dihydroagarofuran-type sesquiterpenoids with ester groups exhibited stronger activity than those with free hydroxy groups or without substituents at the same positions. These results identified a new chemical skeleton as drug lead for the investigation of novel therapeutic agents against AD.

Restoration of Chemosensitivity in P-Glycoprotein-Dependent Multidrug-Resistant Cells by Dihydro-β-agarofuran Sesquiterpenes from Celastrus vulcanicola

Multidrug resistance (MDR) caused by the overexpression of ABC drug transporters is a major obstacle in clinical cancer chemotherapy and underlines the urgent need for the development of new, potent, and safe reversal agents. Toward this goal, reported herein are the structure elucidation and biological activity of nine new (1-9) and four known (10-13) dihydro-β-agarofuran sesquiterpenes, isolated from the leaves of Celastrus vulcanicola, as reversers of MDR mediated by human P-glycoprotein expression. The structures of these compounds were elucidated by extensive NMR spectroscopic and mass spectrometric analysis, and their absolute configurations were determined by circular dichroism studies, chemical correlations (1a, 8a, and 8b), and biogenetic means. Four compounds from this series were discovered as potent chemosensitizers for MDR1-G185 NIH-3T3 murine cells (3, 4, 6, and 7), showing higher efficacies than the classical P-glycoprotein inhibitor verapamil, a first-generation chemosensitizer, when reversing resistance to daunomycin and vinblastine at the lowest concentration tested of 1 μM.

Cytotoxic constituents from Celastrus paniculatus induce apoptosis and autophagy in breast cancer cells

Celastrus paniculatus is a traditional medicinal plant with diverse pharmacological activities. To identify its bioactive constituents, three new β-dihydroagarofuranoid sesquiterpenes were isolated from the whole plant, of which the major constituent is (1α,2α,8β,9β)-1,8-bis(acetyloxy)-2,9-bis(benzoyloxy)-14-hydroxy-β-dihydroagarofuran. It was assessed for its antiproliferative activity, and it suppressed the viability of MCF-7 breast cancer cells with an IC50 of 17±1μM. This growth inhibition was, in part, attributable to apoptosis. Moreover, this drug treatment led to LC3B-II accumulation, indicative of autophagy. Western blot analysis established its ability to target a broad range of signaling effectors related to survival and cell cycle progression, including Akt, NF-κB, p53, and MAP kinases. In addition, flow cytometry analysis indicates increased reactive oxygen species production in response to this compound. Taken together, these findings suggest a pleiotropic mode of mechanism that underlies the antiproliferative activity of this compound in MCF-7 breast cancer cells.