Therapeutic Effect of Ilex hainanensis Merr. Extract on Essential Hypertension: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

With a rapidly aging population, the prevalence of hypertension in adults continues to rise, placing a substantial and escalating social and economic burden. Ilex hainanensis Merr. is commonly used as a folk remedy for treating hypertension, dyslipidemia, and inflammation in China. This systematic review aims to evaluate current evidence for the therapeutic effect of Ilex hainanensis Merr. extract (EIH) on essential hypertension. Six electronic databases (Pubmed, MEDLINE, The Cochrane Central Register of Controlled Trials, Chinese Scientific Journals Database, Wanfang and CNKI) were searched to identify eligible randomized controlled trials (RCTs) relevant to EIH on essential hypertension up to Jan 2018. Six RCTs including 772 participants met eligibility criteria. Methodological quality of the trials was generally low. Meta-analysis showed that EIH demonstrated a beneficial effect for lowering systolic and diastolic blood pressure (SBP/DBP), left ventricular mass (LVM) in participants with essential hypertension. There was no significant difference between EIH and antihypertensive drugs in SBP (WMD: -0.44 [-2.30, 1.43]; P = 0.65), DBP (WMD: WMD: -0.02 [-1.13, 1.09]; P = 0.98) and LVM (WMD: -1.36 [-4.99, 2.26]; P = 0.46). Moreover, one trial showed that EIH combined with antihypertensive drugs was more effective in lowering blood pressure than those antihypertensive drugs used alone. However, the findings were limited by the small sample sizes, duration and low methodological quality of the trials. This is the first systematic review of EIH on essential hypertension. More rigorous RCTs with high quality are still needed to prove the effectiveness and safety of EIH and its preparations for essential hypertension.

Triterpenoids from the leaves of Ilex chinensis

Eleven previously undescribed compounds including two triterpenes, ilexchinenin A and ilexchinenin B, and nine triterpenoid saponins, ilexchinenosides A-I, along with twelve known triterpenoids were isolated from the leaves of Ilex chinensis Sims (Aquifoliaceae). Their structures were elucidated by spectroscopic analysis and comparison with known compounds. Furthermore, eight compounds exhibited significant inhibitory effects on NO production of lipopolysaccharide (LPS)-induced murine macrophages, while nine compounds exhibited potent hepatoprotective activity against N-acetyl-p-aminophenol (APAP)-induced HepG2 cell damage in in vitro assays.

Anti-inflammatory diterpenoids from the root bark of Acanthopanax gracilistylus

Five new ent-pimarane (1-3, 7, and 8) and three new ent-kaurane diterpenoids (4-6) and a new oleanane triterpene acid (9), together with 22 known compounds, were isolated from the root bark of the medicinal herb Acanthopanax gracilistylus. The structures of 1-9 were established based on the interpretation of high-resolution MS and 1D- and 2D-NMR data. The absolute configurations of 7 and 11 were determined by single-crystal X-ray diffraction and electronic circular dichroism analysis. Compounds 7 and 8 represent rare naturally occurring structures based on the devinyl ent-pimarane skeleton. Compounds 3, 10, 14, 16, and 17 exhibited potent inhibitory effects on the release of interleukin-1β (IL-1β), interleukin-8 (IL-8), and tumor necrosis factor (TNF-α) in lipopolysaccharide-stimulated peripheral blood mononuclear cells.

Anti-inflammatory ursane- and oleanane-type triterpenoids from Vitex negundo var. cannabifolia

Six new polyoxygenated triterpenoids, cannabifolins A-F (1-6), and eight known triterpenoids, 7-14, were isolated from the leaves of Vitex negundo var. cannabifolia. The absolute configuration of cannabifolin A (1) was determined by single-crystal X-ray crystallographic analysis. Compounds 1 and 2 represent a class of rare natural pentacyclic triterpenoids bearing cis-fused C/D rings and are the first examples of 12,19-epoxy ursane- and oleanane-type triterpenoids. Compounds 3, 7, 8, and 14 exhibited inhibition of nitric oxide production in lipopolysaccharide-induced RAW 264.7 macrophages with IC50 values in the range 24.9-40.5 μM.

Analysis of Therapeutic Effect of Ilex hainanensis Merr. Extract on Nonalcoholic Fatty Liver Disease through Urine Metabolite Profiling by Ultraperformance Liquid Chromatography/Quadrupole Time of Flight Mass Spectrometry

Nonalcoholic fatty liver disease (NAFLD), the most common form of chronic liver disease, is increased worldwide in parallel with the obesity epidemic. Our previous studies have showed that the extract of I. hainanensis (EIH) can prevent NAFLD in rat fed with high-fat diet. In this work, we aimed to find biomarkers of NAFLD and investigate the therapeutic effects of EIH. NAFLD model was induced in male Sprague-Dawley rats by high-fat diet. The NAFLD rats were administered EIH orally (250 mg/kg) for two weeks. After the experimental period, samples of 24 h urine were collected and analyzed by ultraperformance liquid chromatography/quadrupole time of flight mass spectrometry (UPLC-Q-TOF). Orthogonal partial least squares analysis (OPLSs) models were built to find biomarkers of NAFLD and investigate the therapeutic effects of EIH. 22 metabolites, which are distributed in several metabolic pathways, were identified as potential biomarkers of NAFLD. Taking these biomarkers as screening indexes, EIH could reverse the pathological process of NAFLD through regulating the disturbed pathway of metabolism. The metabolomic results not only supply a systematic view of the development and progression of NAFLD but also provide a theoretical basis for the prevention or treatment of NAFLD.

Triterpenoid-Rich Fraction from Ilex hainanensis Merr. Attenuates Non-Alcoholic Fatty Liver Disease Induced by High Fat Diet in Rats

Non-alcoholic fatty liver disease (NAFLD) has become a major challenge to the healthcare system. This study was designed to evaluate the effect of the triterpenoid-rich fraction (TF) from Ilex hainanensis Merr. on NAFLD. Male Sprague-Dawley (SD) rats were fed a normal diet (control) or high fat diet (NAFLD model). After four weeks, the high fat diet group was orally administrated TF (250 mg/kg) for another two weeks. High fat diet fed rats displayed hyperlipidemia and a decline in liver function compared with control. However, administration with TF could effectively improve these symptoms, as demonstrated by decreasing the plasma levels of triglyceride (p <0.05), total cholesterol (p < 0.01), low-density lipoprotein cholesterol (p < 0.05), alanine transaminase (p < 0.05), aspartate aminotransferase (p < 0.01), liver index (p < 0.05) and insulin resistance index (p < 0.05) while increasing the high-density lipoprotein cholesterol (p < 0.05). Meanwhile, histopathological examination of livers also showed that TF could reduce the incidence of liver lesions induced by high fat diet. Furthermore, TF could alleviate oxidative stress and inflammation status indicated by the decline malondialdehyde and superoxide dismutase levels (p < 0.01, both) and levels of interleukin 6 and tumor necrosis factor-α (p < 0.05). In addition, immunohistochemistry showed TF evidently elevated the peroxisome proliferator-activated receptor (PPARα) expression (p < 0.01), while it diminished the Cytochrome P450 2E1 (CYP2E1) expression (p < 0.01) in liver. These results demonstrate that TF has potential ability to protect liver against NAFLD by regulating lipids metabolism and alleviating insulin resistance, inflammation and oxidative stress. This effect might be associated with regulating PPARα and CYP2E1 expression.

Triterpenoids

This review covers the isolation and structure determination of triterpenoids including squalene derivatives, protostanes, lanostanes, holostanes, cycloartanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, lupanes, oleananes, friedelanes, ursanes, hopanes, isomalabaricanes and saponins; 574 references are cited.

Complete assignments of 1H and 13C NMR spectral data for three new triterpenoid saponins from Ilex hainanensis Merr

Three new oleanane-type triterpenoid saponins, ilexhainanoside C, D and E, all with 24, 28-dioic acid groups, were isolated from the leaves of Ilex hainanensis. They were 3beta-hydroxyolean-12-ene-24, 28-dioic acid-28-O-beta-D-glucopyranoside(1), 3beta, 19alpha-dihydroxyolean-12-ene-24, 28-dioic acid-28-O-beta-D-glucopyranoside(2) and 3beta, 29-dihydroxyolean-12-ene-24, 28-dioic acid-28-O-beta-D-glucopyranoside(3). The structures of these three new compounds were elucidated and complete assignments of the (1)H and (13)C NMR spectroscopic data were achieved by 1D and 2D NMR experiments [heteronuclear single quantum coherence (HSQC), HMBC and rotational nuclear Overhauser effect spectroscopy (ROESY)].