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.

An extensive review on phytochemistry and pharmacological activities of Indian medicinal plant Celastrus paniculatus Willd

Celastrus paniculatus is a traditional herb belonging to the family Celastraceae and is widely used for a number of medicinal activities in the Indian Unani and Ayurvedic systems. In this study, the extensive literature search was carried out on phytochemistry, ethnobotanical uses and pharmacological activities of C. paniculatus (Willd.) in various scientific databases as well as patents. Research on phytochemical investigation has shown the presence of monoterpenes (linalool, α-terpinyl acetate, nerol acetate), sesqueterpene esters (such as malkanguniol, malkangunin, valerenal, globulol, viridiflorol, cubenol and agarofuran derivatives), diterpenoids (such as phytone, isophytol), triterpenoids (such as lupeol, pristimerin, paniculatadiol, zeylasteral, zeylasterone, β-amyrin, squalene), alkaloids (celapanin, celapanigin, celapagin, paniculatine, celastrine, maymyrsine), fatty acids, steroids (β-sitosterol, carpesterol benzoate), flavonoids (paniculatin), benzoic acid, and vitamin C in this plant. All the reported pharmacological activities of this plant could be due to the presence of these phytochemicals. This plant possesses strong antioxidant activity which includes total flavonoid content, total phenolic content, nitric oxide scavenging activity and free radical scavenging activity. This plant possesses multiple pharmacological activities including cognition-enhancing, neuroprotective, antipsychotic, anti-depressant, antibacterial, anti-arthritic, anti-malarial, analgesic, anti-inflammatory, anti-fertility, cardiovascular, locomotor, anxiolytic, wound healing activity, anti-spasmodic, hypolipidemic, anti-cancerous and iron-chelating activity with different extracts of this plant as well as various phytoconstituents present in this plant. The objective of this review article is to discuss in detail the reported ethnopharmacological uses, phytochemistry and various pharmacological activities of C. paniculatus.

In Vitro Susceptibility of Kinetoplastids to Celastroloids from Maytenus chiapensis

Leishmaniasis and Chagas are among the most significant neglected tropical diseases. Due to several drawbacks with the current chemotherapy, developing new antikinetoplastid drugs has become an urgent issue. In the present work, a bioassay-guided investigation of the root bark of Maytenus chiapensis on Leishmania amazonensis and Trypanosoma cruzi led to the identification of two D:A-friedo-nor-oleanane triterpenoids (celastroloids), 20β-hydroxy-tingenone (celastroloid 5) and 3-O-methyl-6-oxo-tingenol (celastroloid 8), as promising antikinetoplastid leads. They displayed higher potency on L. amazonensis promastigotes (50% inhibitory concentrations [IC50s], 0.44 and 1.12 μM, respectively), intracellular amastigotes (IC50s, 0.83 and 1.91 μM, respectively), and T. cruzi epimastigote stage (IC50s, 2.61 and 3.41 μM, respectively) than reference drugs miltefosine and benznidazole. This potency was coupled with an excellent selectivity index on murine macrophages. Mechanism of action studies, including mitochondrial membrane potential (Δψm) and ATP-level analysis, revealed that celastroloids could induce apoptotic cell death in L. amazonensis triggered by the mitochondria. In addition, the structure-activity relationship is discussed. These findings strongly underline the potential of celastroloids as lead compounds to develop novel antikinetoplastid drugs.

Non-nitrogenous Plant-derived Constituents with Antiplasmodial Activity

The paper is a compilation of the studies reported in the literature concerning non-nitrogenous natural constituents that have shown antiplasmodial activity and aims to provide a basis for further in vivo studies as well as for clinical trials to develop new antimalarial agents. Due to the increasingly unsatisfactory outcomes for N-heterocyclic drugs, coupled with the rising incidence of the deadly falciparum malaria, the advent of non-nitrogenous lead compounds is timely, signaling a new era of antimalarial chemotherapy. Currently a few non-nitrogenous molecules are used in therapy, but many promising molecules of plant origin are under study, such as peroxide sesquiterpenes, quinoid triterpenes, quassinoids, gallic acid derivatives, lignans, flavonoids and biflavonoids, xanthones, naphthoquinones and phenylanthraquinones. Many of these constituents are isolated from plants used traditionally to treat malaria and fever. Ethnopharmacology can still be considered as a rich source of lead molecules.

Antiplasmodial potential of traditional phytotherapy of some remedies used in treatment of malaria in Meru-Tharaka Nithi County of Kenya

ETHNOPHARMACOLOGICAL RELEVANCE

Medicinal plants play a major role in many communities across the world, in the treatment and prevention of disease and the promotion of general health. The aim of the study was to escalate documentation from an earlier study of medicinal plants, traditionally used to combat malaria by the Ameru community of Imenti Forest area and Gatunga in Eastern Region of Kenya, and validate their ethnopharmacological claims by evaluating their antiplasmodial efficacies.

MATERIALS AND METHODS

The study was carried out in Meru County at Imenti Forest Game Reserve and in Tharaka Nithi County at Gatunga. Traditional health practitioners (THP) were interviewed with a standard questionnaire to obtain information on medicinal plants traditionally used for management of malaria. Group interviews were also held among THPs and members of the community. The antiplasmodial activities of the crude extracts against chloroquine sensitive (D6) and resistant (W2) Plasmodium falciparum were determined using the semi-automated micro-dilution technique that measures the ability of the extracts to inhibit the incorporation of (G-3H) hypoxanthine into the malaria parasite.

RESULTS

Ninety nine (99) species in eighty one (81) genera and forty five (45) families were documented and evaluated for in vitro antiplasmodial activity. Compositae, Fabaceae, Meliceae, Rubiaceae, Rutaceae and Verbenaceae had the highest number of species mentioned in treatment of malaria in Meru/Tharaka Nithi study area. Twenty four (24.2%) species showed antiplasmodial efficacy of IC50 ≤ 5 µg/ml and were considered to have potential for isolation of antimalarial compounds. Eight plant (8) species with moderate antiplasmodial activity namely; Cordia africana, Commiphora africana, Elaeodendron buchananii, Gomphocarpus semilunatus, Tarena graveolens, Plectranthus igniarius, Acacia senegal and Ziziphus abyssinica were documented from this region for the first time for the treatment of malaria. The antiplasmodial activity of MeOH root bark extract of Maytenus obtusifolia was very promising (IC50 < 1.9 µg/ml) and this is the first report on traditional use of M. obtusifolia for treatment of malaria and antimalarial activity.

CONCLUSIONS

The results seem to indicate that ethnopharmacological inquiry used in search for new herbal remedies as predictive and could be used as the basis for search of new active principles. Eight plant (8) species are documented from this region for the first time for the treatment of malaria. This is the first report on traditional use of M. obtusifolia for treatment of malaria and evaluation of its antiplasmodial activity.

Antioxidant quinonemethide triterpenes from Salacia campestris

A new quinonemethide triterpene named as salacin, has been isolated from the root bark of Salacia campestris in addition to the known pristimerin, maytenin, 20alpha-hydroxymaytenin, and netzahualcoyene. Salacin was identified on the basis of NMR-spectral and mass spectrometric analysis. The free-radical scavenging activities of the quinonemethide triterpenes salacin (1), pristimerin (2), maytenin (3), 20alpha-hydroxymaytenin (4), and netzahualcoyene (5) towards DPPH have been evaluated and showed absorbance variation (deltaA) of 19, 20, 39, 28, 55, and 10%, respectively, having rutin (74% at 50 microM) and BHT (7% at 50 microM) as standard compounds.

Detection and identification of quinonemethide triterpenes in Peritassa campestris by mass spectrometry

Analysis of tingenone and tingenol quinonemethide triterpenes was made by gas chromatography/mass spectrometry (GC/MS) of their trimethylsilyl (TMS) ethers. An extra TMS group, in addition to those predicted from the known structures, is added to these compounds during the derivatization process. The electron impact mass spectra showed base peaks at m/z 549 and 623, respectively, for the TMS derivatives of tingenone and tingenol, and electrospray (ES) and collision-activated dissociation (CAD) studies indicate that these ions correspond to losses of a methyl group from the derivatives studied. A mechanism, based on ES-MS/MS studies, is suggested for the derivatization and fragmentation pattern.

Biosynthesis of friedelane and quinonemethide triterpenoids is compartmentalized in Maytenus aquifolium and Salacia campestris

Maytenus aquifolium (Celastraceae) and Salacia campestris (Hippocrateaceae) species accumulate friedelane and quinonemethide triterpenoids in their leaves and root bark, respectively. Enzymatic extracts obtained from leaves displayed cyclase activity with conversion of the substrate oxidosqualene to the triterpenes, 3beta-friedelanol and friedelin. In addition, administration of (+/-)5-(3)H mevalonolactone in leaves of M. aquifolium seedlings produced radio labelled friedelin in the leaves, twigs and stems, while the root bark accumulated labelled maytenin and pristimerin. These experiments indicated that the triterpenes once biosynthesized in the leaves are translocated to the root bark and further transformed to the antitumoral quinonemethide triterpenoids.

In vitro and in vivo evaluation of betulinic acid as an antimalarial

The lupane-type triterpene betulinic acid was isolated from an ethanol extract of the root bark of the Tanzanian tree Uapaca nitida Müll-Arg. (Euphorbiaceae). The in vitro antiplasmodial IC50 values of betulinic acid against chloroquine resistant (K1) and sensitive (T9-96) Plasmodium falciparum were found to be 19.6 micrograms/mL and 25.9 micrograms/mL, respectively. The in vitro activities of several related triterpenes were also evaluated. Betulin was found to be inactive at 500 micrograms/mL for both K1 and T9-96. Ursolic acid exhibited IC50 values of 36.5 micrograms/mL and 28 micrograms/mL, and oleanolic acid exhibited IC50 values of 88.8 micrograms/mL and 70.6 micrograms/mL against K1 and T9-96, respectively. When betulinic acid was tested for in vivo activity in a murine malaria model (P. berghei) the top dosage employed of 250 mg/kg/day was ineffective at reducing parasitaemia and exhibited some toxicity. Betulinic acid has not previously been evaluated for in vivo activity. This is believed to be the first compound to be isolated from U. nitida.

Quinone-methide triterpenoids from Glyptopetalum sclerocarpum

Nine novel quinone-methide triterpenoids: 20-hydroxytingenone, 20,22beta-dihydroxytingenone, 20,22beta-dihydroxy-20-epi-tingenone, 20,21alpha-dihydroxy-22-oxo-21-desoxotingenone, 20-hydroxy-22-oxotingenone, 20-hydroxy-22-oxo-20-epi-tingenone, 21alpha-hydroxy-20,22-dioxo-30(20-->21)abeo-21-desoxotingenone, 20-oxo-20,21-seco-tingen-21-oic acid and 20-oxo-21-nor-20,21-seco-tingen-22-al, were isolated from the stem bark of Glyptopetalum sclerocarpum. Their structures were determined on the basis of spectroscopic evidence.

Can ethnopharmacology contribute to the development of antimalarial agents?

The resistance of Plasmodium falciparum, the cause of tertian malaria, to synthetic antimalarials, together with the resistance of the vector mosquitoes to insecticides, has resulted in a resurgence in the use of quinine and a search for new antimalarial agents. In recent years, artemisinin, isolated from Artemisia annua which is used in Chinese traditional medicine for the treatment of malaria, has proved to be effective in the treatment of cerebral malaria due to chloroquine-resistant strains of P. falciparum. The development of in vitro tests utilising P. falciparum obtained from malaria patients means that it is possible to use bioassay guided fractionation of active extracts in order to isolate active principles. A number of laboratories throughout the world are currently investigating plants used in traditional medicine for their active constituents. Some of their results will be described and in particular two aspects of our investigations with species of Simaroubaceae and Menispermaceae will be discussed. There is every possibility that such approaches which use leads from Ethnopharmacology will result in the development of new antimalarial agents. It is vitally important to those populations relying on traditional medicines for the treatment of malaria that the safety and efficacy of such medicines be established, their active principles determined and that reproducible dosage forms be prepared and made available for use.

The triterpene celastrol as a very potent inhibitor of lipid peroxidation in mitochondria

The inhibitory effect of the dienone-phenolic triterpene, celastrol, on lipid peroxidation in rat liver mitochondrial membranes induced by ADP and Fe2+ was studied. The anti-peroxidative effect of celastrol was very strong: its 50% inhibitory concentration was 7 microM, and it was about 15 times more effective than alpha-tocopherol. Celastrol scavenged 1.5 molar equivalents of radicals in homogeneous aqueous ethanolic solution, whereas cysteine and alpha-tocopherol scavenged one and two molar equivalents of radicals, respectively. The process of anti-peroxidation of celastrol was biphasic, possibly due to stepwise inhibitions of peroxidation in the outer and inner mitochondrial membranes.