Preparative separation and purification of five anthraquinones from Cassia tora L. by high-speed counter-current chromatography

The genus Cassia L.: Ethnopharmacological and phytochemical overview

Nature gifts medicinal plants with the untapped and boundless treasure of active chemical constituents with significant therapeutic potential that makes these plants a beneficial source in the development of phytomedicines. Genus Cassia, with approximately 500 species, is a large group of flowering plants in the family Fabaceae. Cassia species are widely distributed throughout different regions mainly tropical Asia, North America, and East Africa. In the folk medicinal history, these plants are used as laxative and purgative agents. In the Ayurveda system of medicine, they are used to cure headache and fever. Cassia plants exhibit pharmacological activities at large scales such as antimicrobial, anticancer, antiinflammatory, antioxidant, hypoglycemic, hyperglycemic, antimutagenic, and antivirals. The phytochemical investigations of genus Cassia demonstrate the presence of more than 200 chemical compounds, including piperidine alkaloids, anthracene derivatives (anthraquinones), flavonoids, pentacyclic triterpenoids, sterols, phenylpropanoids, and γ-naphthopyrones. The literature illustrated anthraquinones and flavonoids as major secondary metabolites from this genus. However, some Cassia plants, with rich contents of anthraquinones, still show toxicology properties. As Cassia plants are used extensively in the herbal system of medicine, but only senna dosage forms have achieved the status of the pharmaceutical market as standard laxative agents. In conclusion, further investigations on isolating newer biologically active constituents, unknown underlying mechanisms, toxicology profiles, and clinical studies of Cassia species are needed to be explored. This review article specifies the systematic breach existing between the current scientific knowledge and the fundamentals for the marketization of genus Cassia products.

Isolation of six anthraquinone diglucosides from cascara sagrada bark by high-performance countercurrent chromatography

In this study, high-performance countercurrent chromatography was employed to isolate six anthraquinone diglucosides, namely, cascarosides A-F, from cascara sagrada (Rhamnus purshiana DC [Rhamnaceae]) bark. The n-butanol-soluble extract of cascara sagrada was separated by off-line two-dimensional high-performance countercurrent chromatography. The first-dimensional high-performance countercurrent chromatography resolved the n-butanol-soluble extract (510 mg) of cascara sagrada using the flow-rate gradient method with a chloroform-methanol-isopropanol-water (6:6:1:4, v/v/v/v, normal-phase mode) system to afford four anthraquinone diglucoside fractions (groups I [cascarosides C-D, 71 mg], II [cascarosides E-F, 56 mg], III [cascaroside A, 53 mg], and IV [cascaroside B, 31 mg]). Groups I and II were separated by the second-dimensional high-performance countercurrent chromatography using an ethyl acetate-n-butanol-water (7:3:10, v/v/v, normal-phase mode) system to yield cascarosides C (34 mg), D (26 mg), E (19 mg), and F (15 mg). Additionally, one-step preparative-scale high-performance countercurrent chromatography method was developed to isolate large amounts of cascarosides A (389 mg) and B (187 mg) from the water-soluble extract (2.1 g) of cascara sagrada using an ethyl acetate-n-butanol-water (2:8:10, v/v/v, normal-phase mode) system. The current study demonstrated that high-performance countercurrent chromatography is a powerful technique for the isolation of marker compounds from herbal materials.

Pyranonaphthoquinone and anthraquinone derivatives from Ventilago harmandiana and their potent anti-inflammatory activity

The chemical study on the heartwoods extract of Ventilago harmandiana (Rhamnaceae) resulted in the isolation of ten previously undescribed pyranonaphthoquinones (ventilanones A-J), an undescribed anthraquinone (ventilanone K), together with eight known anthraquinone derivatives. Their structures were elucidated by extensive analysis of their spectroscopic data. The absolute configuration of ventilanone A was established from single crystal X-ray crystallographic analysis of its p-bromobenzenesulfonate ester derivative using Cu Kα radiation. The absolute configurations of the other related compounds were identified by comparison of their ECD data with those of ventilanone A and related known compounds. Cytotoxic and anti-inflammatory activities of some of the isolated compounds were evaluated. Ventilanone A and ventilanone C exhibited moderate cytotoxicity against P-388 cell line. Ventilanone D exhibited significant anti-inflammatory activity while ventilanone A and ventilanone C showed moderate activity.

Escalation of liver malfunctioning: A step toward Herbal Awareness

ETHNOPHARMACOLOGICAL RELEVANCE

About 2-5% of the world's population is suffering from liver toxicity including Pakistan with the second highest rate of hepatitis prevalence. Liver is a vital body organ which not only performs metabolic activities but also aids in detoxification, storage and digestion of food. Now a day's malnutrition, alcohol consumption and drug addiction are major causes of liver diseases throughout the world. In fact, there is no possible outcome to compensate liver malfunction for long term, and transplantation of liver is the only option left after the irretrievable injury of hepatic function. Subsequently, natural based therapeutic approaches are in the process of scrupulous testing as strong hepatoprotective mediator. In this regard plants are well thought hepatoprotective agents having multiple active components. In this review, based on species' pharmacology and safety we have compiled some plants which show strong hepatoprotective activity, main phytoconstituents with biological activities and few commercially used herbal formulations.

MATERIALS AND METHODS

Ethnopharmacological information was gathered by an extensive literature survey like WHO monographs on selected herbal medicinal plants (Vol 1-Vol 4); Principles and Practice of Phytotherapy, Mills S and Bone K, Churchill Livingstone, London, UK; Herbal Drugs and Phytopharmaceuticals, Wichtl M Medpharm Press, Stuttgart 3rd edn; Pharmacology and Applications of Chinese Materia Medica Vols 1 and 2, Chang H-M and But P P-H World Scientific, Singapore; British Herbal Compendium Vol. 2, Bradley P British Herbal Medicine Association, Bournemouth, UK; ESCOP Monographs 2nd edn. Thieme, Stuttgart, Germany; as well as by using electronic databases such as Pubchem, Chemspider, http://www.herbal-ahp.org; http://www.ahpa.org; http://whqlibdoc.who.int/publications/2003/9241546271.pdf; http://www.escop.com, Pubmed, HubMed and Scopus.

RESULTS

Data for more about 29 plants have been accomplished for their bioactive constituent(s), biological activities and medicinal uses. Some of the plants have been identified as strong hepato-modulator. Such knowledge about traditional medicinal plants can be globally applied for safe and evidence based use in pharmacological applications.

CONCLUSION

With the rise in liver risks a meek struggle has been made to draw attention toward herbal therapy. Hepatoprotective constituents of said plants are expressed with chemical structures. However, for certain plants active constituents are not still isolated/purified but overall plant extract was found effective in providing protection against hepatic injury. As a future perspective, there is need to purify plant active constituents for ethnomedical rationale.

A theoretical study of UV-Vis spectrum and antioxidant activity of chryso-obtusin

The conformation, electron structure, and antioxidant mechanism of chryso-obtusin, extracted from Leguminosae of traditional Chinese herb, have been studied in CH3OH by the density functional theory B3LYP/PCM/6-311[Formula: see text]G(2df,p)//B3LYP/PCM/6-31G([Formula: see text]) method. Three mechanisms of antioxidant actions are examined, which contain hydrogen atom transfer (HAT), single-electron transfer-proton transfer (SET-PT), and sequential proton loss transfer (SPLET), by using the computed corresponding indicators (BDE, IP, and PDE). Still, the spin density is employed to measure the delocalization of the antioxidant and its radical form. The finding suggests that hydrogen bond interaction is the main cause for the antioxidant activity of this antioxidant.

An ethnobotanical survey of medicinal plants used by communities of Northern Kordofan region, Sudan

ETHNOPHARMACOLOGICAL RELEVANCE

The present study provides significant ethnopharmacological information on plant species used in North Kordofan region, western Sudan. The study was undertaken with an aim to document the medicinal uses of the species known to some Northern Kordofan communities.

MATERIAL AND METHODS

The study was conducted between 2012 and 2013. The plants were identified and voucher specimens prepared. Information was collected by means of semi-structured interviews with 258 informants (195 men and 63 women). In addition, the use value (UV) of the species was determined and the informant consensus factor (ICF) was calculated for the medicinal plants researched in the study. Further analysis was carried out to compare results with previous studies from the study area and other regions of Sudan.

RESULTS

A total of 44 plant species representing 24 families were found to be commonly used in the treatment of 73 different human health problems. The families most represented were Leguminosae (18%), Caesalpiniaceae (9%), Malvaceae (9%), Asclepiadaceae (6.8%) and Combretaceae (6.8%). The highest number of plant species are used against digestive system disorders (23 species) followed by microbial infections (21 species) and dermatology (19 species). Among all the plant parts leaves (20%), roots (19%), fruits and bark (14% each) were the most preferred plant parts used by the informants. There was strong agreement among the informants as to the usages of the plants (informant consensus factor 0.63-0.93). The most important plants on the basis of use-value were Acacia nilotica, Acacia seyal, Balanites aegyptiaca, Cassia occidentalis, Cassia senna, Guiera senegalensis and Tamarindus indica.

CONCLUSION

This study has helped to document information that may otherwise be lost to future generations. This is the first ethnobotanical study in which statistical calculations about plants are carried out by means of the ICF and UV methods in the study area. Plants with high ICF and UV values should be subjected for further phytochemical and pharmacological investigation for scientific validation.

DFT INSIGHT INTO THE UV-VIS SPECTRA AND RADICAL SCAVENGING ACTIVITY OF AURANTIO-OBTUSIN

Aurantio-obtusin (2,6,8-trihydroxy-1,7-dimethoxy-3-methyl anthraquinone), an anthraquinone derivative isolated from the seeds of Cassia tora L., has been studied by DFT calculations at the B3LYP/6-311+g(2df,p)//B3LYP/6–31G(d,p) level in vacuum and in methanol polarized continuum model (PCM). Eight conformers have been located by conformational search and optimization. Our results indicate that the titled compound has planar structures, and five intramolecular hydrogen bonds are found in the lowest-energy structure, including three OH⋯O and two CH⋯O hydrogen bonds. The electronic spectra in methanol have been determined by the time-dependent density functional theory (TD-DFT) approach, showing that the first singlet exited state of the title compound arises from π → π* electron transition. The antioxidant activity of aurantio-obtusin is evaluated by means of calculating O−H bond dissociated enthalpy (BDE) and the adiabatic ionization energy (IE). The calculated BDE and IE values of aurantio-obtusin are 341.8 and 732.3 kJ mol-1, respectively, lower than the corresponding values of phenol (348.4 and 801.7 kJ mol-1) and purpurin (360.4 and 747.8 kJ mol-1), suggesting that aurantio-obtusin is a better antioxidant.

Preparative isolation of alkaloids from Corydalis bungeana Turcz. by high-speed counter-current chromatography using stepwise elution

High-speed counter-current chromatography (HSCCC) was successfully applied for the preparative separation and purification of alkaloids from Corydalis bungeana Turcz. (Kudiding in Chinese) for the first time. After the measurement of partition coefficient of seven target alkaloids in the nine two-phase solvent systems composed of CHCl(3)-MeOH-(0.1 M; 0.2 M; 0.3 M) HCl (4:1.5:2; 4:2:2; 4:3:2, v/v), CHCl(3)-MeOH-0.2 M HCl (4:2:2, v/v) and CHCl(3)-MeOH-0.3 M HCl (4:3:2, v/v) were finally selected for the HSCCC separation using the first upper phase as the stationary phase and the stepwise elution of the two lower mobile phases. Consequently, sanguinarine (10 mg), corynoline (25 mg), protopine (20 mg), corynoloxine (18 mg), and 12-hydroxycorynoline (8 mg) were obtained from 200 mg of crude alkaloid extracts with purities of 94-99% as determined by HPLC. Their chemical structures were characterized on the basis of (1)H-NMR, (13)C-NMR, and LC-ESI-Q-TOF-MS/MS analyses.

Preparative isolation of three anthraquinones from Rumex japonicus by high-speed counter-current chromatography

Three anthraquinones—emodin, chrysophanol, and physcion—were successfully purified from the dichloromethane extract of the Chinese medicinal herb Rumex japonicus by high-speed counter-current chromatography (HSCCC). The extract was separated with n-hexane–ethanol–water (18:22:3, v/v/v) as the two-phase solvent system and yielded 3.4 mg of emodin, 24.1 mg of chrysophanol, and 2.0 mg of physcion from 500 mg of sample with purities of 99.2 %, 98.8% and 98.2%, respectively. The HSCCC fractions were analyzed by high-performance liquid chromatography (HPLC) and the chemical structures of the three anthraquinones were confirmed by ¹H-NMR and ¹³C-NMR analysis. This is the first time these anthraquinones have been obtained from R. japonicus by HSCCC.

Semi-preparative high-speed counter-current chromatography separation of alkaloids from embryo of the seed of Nelumbo nucifera Gaertn by pH-gradient elution

A new high-speed counter-current chromatography method for semi-preparative separation and purification of alkaloids from embryo of the seed of Nelumbo nucifera Gaertn was developed by using pH-gradient elution mode. Diethyl ether was used as the stationary phase of the two-phase solvent system and Na(2)HPO(4)/NaH(2)PO(4) buffer solution with pH values of 7.5 and 7.2 in gradient mode as the mobile phase. Consequently, 33 mg of liensinine, 42 mg of isoliensinine, and 67 mg of neferine were obtained from 200 mg of crude extracts. The purities of them were all over 98% as determined by HPLC area normalization method, and the structures were identified by (1)H-NMR and (13)C-NMR.