Discovery and structure-activity relationship of auriculatone: A potent hepatoprotective agent against acetaminophen-induced liver injury.

Acetaminophen (APAP, paracetamol) overdose has been the most frequent cause of drug-induced liver failure. APAP-induced liver toxicity can be fatal in many cases even with treatment of the clinically used N-acetylcysteine (NAC), and the need for novel therapeutic agents is apparent. Through evaluating the hepatoprotective effects of the co-occurring substances present in oleanolic acid tablets which have been used in China for decades as an adjuvant therapy for acute and chronic hepatitis, auriculatone was found to protect HL-7702 cells from APAP-induced liver injury comparable to NAC at the concentration of 10µM. Structure activity relationship on auriculatone and its analogs showed that absence of the C17 carboxyl group of auriculatone was essential to achieve good hepatoprotective activity, and that the C3-OH, C16 carbonyl and C12-C13 olefinic group were critical for retaining the exceptional activity of auriculatone. Any modifications in the current investigation were all detrimental to the hepatoprotective activity. Docking and drug-metabolizing activity studies demonstrated that CYP3A4 was likely the main target of auriculatone, and that auriculatone elicited the hepatoprotective effect possibly through inhibiting CYP3A4's metabolism of APAP to the toxic metabolite NAPQI. The work may pave the way for the use of auriculatone in the treatment of APAP-induced liver injury.

Identification of anti-inflammatory constituents from Kalimeris indica with UHPLC-ESI-Q-TOF-MS/MS and GC-MS.

ETHNOPHARMACOLOGICAL RELEVANCE: Kalimeris indica is a Miao׳s medicinal plant in Guizhou province of China employing to treat various inflammation-related diseases in clinical. The study aims to determine the active fractions of K. indica for its anti-inflammatory activity and to identify their chemical constituents. MATERIAL AND METHODS: The dried K. indica herb was extracted with 50% aqueous ethanol and then successively separated with macroporous resin and MCI column chromatography to give five fractions (A-E). The anti-inflammatory effects were determined by measuring the NO and TNF-α production in murine macrophage RAW 264.7 cells after exposure to LPS. The chemical constituents of the anti-inflammatory fractions were analyzed by the method of UHPLC-ESI-Q-TOF/MS or GC-MS. RESULTS: Five fractions (A-E) of different polarities were prepared from the 50% ethanol extract. Factions C and E showed significant inhibition of NO and TNF-α production. Six constituents, namely 3,4-dicaffeoylquinic acid (1), 3,5-dicaffeoylquinic acid (2), 1,5-dicaffeoylquinic acid (3), rutin (4), 1-malonyl-3,5-dicaffeoylquinic acid (5), and 4,5-dicaffeoylquinic acid (6) were identified from the active fraction C by UHPLC-ESI-Q-TOF/MS. Four compounds including 13-tetradecenal (7), (Z,Z)-9,12-octadecadienoic acid (8), (3α)-12-oleanen-3-yl acetate (9), and (+)-3-oxo-urs-12-en-24-oic acid methyl ester (10) were identified from the active fraction E by GC-MS. CONCLUSION: K. indica possessed pronounced anti-inflammatory effect. Dicaffeoylquinic acids and their dirivatives, rutin, as well as oleanolic and fatty acid derivatives are the major constituents and possibly the anti-inflammatory principles of the active fractions of K. indica. All the compounds were identified in K. indica for the first time. The work provided evidence for further development and utilization of K. indica and formed a basis for the establishment of quality control methods and standards for K. indica and its pharmaceutical preparations.

Protective effects of fractions from Pseudostellaria heterophylla against cobalt chloride-induced hypoxic injury in H9c2 cell.

ETHNOPHARMACOLOGICAL RELEVANCE: Except for as a well-known tonic Chinese herbal medicine for the treatment of splenic asthenia, anorexia, lassitude and weakness, the roots of Pseudostellaria heterophylla was also used in Chinese medicines for the treatment of palpitation. AIM OF THE STUDY: The study was designed to determine whether fractions from Pseudostellaria heterophylla could provide cardioprotection on hypoxic cardiomyocytes, what structural types of compounds were responsible for the observed effects, and which is the possible mechanism of action. MATERIALS AND METHODS: The roots of Pseudostellaria heterophylla were extracted successively with 70% aqueous ethanol and water to give a 70% ethanol extract and a water extract. The latter was first precipitated by 80% ethanol and then protein-removed by the Sevag method to give a fraction enriched in polysaccarides (PHP). The former was separated by column chromatography into a fraction enriched in small-molecule sugars and amino acids (PHSSAC), saponins (PHS), cyclopeptides (PHCP), and sapogenins (PHSG). UV spectral or chemical methods were used to confirm the five fractions. The cardioprotective effects of the fractions were evaluated by measuring the viability and the leakage of lactate dehydrogenase (LDH) of the fraction-pretreated cardiomyocyte H9c2 after exposure to CoCl2-induced hypoxia. The mechanism of action was studied by investigating the nature of cell death inhibition (by Annexin V/PI flow cytometric analysis) and their effects on the levels of malonaldehyde (MDA), superoxide dismutase (SOD) and intracellular reactive oxygen species (ROS). RESULTS: Fractions PHS and PHP could attenuate CoCl2-induced hypoxic damage to an extent higher than or comparable to the effect of the positive control N-acetyl-l-cysteine (NAC). Pretreatment of the cells with 800 µg/mL of PHS or 10mg/mL of PHP markedly decreased the level of MDA, reduced intracellular ROS, increased the activity of SOD, and reduced leakage of LDH to the levels close to or better than that with 326 µg/mL of NAC. Reduction of apoptosis was also observed for both fractions. CONCLUSIONS: The overall results suggested that the traditional use of this plant for the treatment of palpitation may be attributed to the presence of cardioprotective agents in Pseudostellaria heterophylla. PHP and PHS were the two active fractions responsible for its cardioprotective effect. The mechanism might involve protections of the cell membrane from hypoxic damage and of the cells from oxidative injury via preventing increased oxidative stress. Protection of the cells via inhibition of cellular apoptosis may also be involved.