In vitro inhibition by 79 herb injectables of nine human cytochrome P450 isoenzymes: a systematic evaluation of herb-drug interactions / 药学学报

Seventy-nine injectable herb extractions have been approved by the Chinese Food and Drug Administration (CFDA) and are frequently administered intravenously for various diseases. Unfortunately, herb-drug interactions are under-investigated and sometimes overlooked in the clinic. In the present investigation the in vitro inhibition of 9 drug metabolizing enzymes including CYP1A, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A was assessed using an appropriate probe substrate for each enzyme with human liver microsomes. Metabolite formation was quantified using a validated and sensitive high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay. The IC50 of each herb extract was estimated using a concentration range from 5% to 0.5%, and the time-dependent inhibition of the nine CYP450 isoenzymes was also determined. Of the 79 approved iv herb injectables, 37 inhibited CYP1A, 24 inhibited CYP2A6, 41 inhibited CYP2B6, 36 inhibited CYP2C8, 31 inhibited CYP2C9, 41 inhibited CYP2C19, 13 inhibited CYP2D6, 25 inhibited CYP2E1, and 42 inhibited CYP3A with 50% or greater inhibition at a test concentration of 5% (v/v). IC50 differences were noted between pre-incubation or co-incubation assays with HLM for 30 min, with the time-dependent inhibitory (TDI) effects were observed with 2 injectables on CYP1A, 5 injectables on CYP2A6, 5 injectables on CYP2B6, 6 injectables on CYP2C8, 1 injectable on CYP2D6 and 6 injectables on CYP3A. Collectively, the results demonstrate that potential herb-drug interactions (HDIs) can occur with the concomitant use of herb injectables and prescription drugs that are cleared by CYP450 enzymes, and further investigation is warrant for the clinical relevance of these interactions.

Effect of herbal extracts on bone regeneration in a rat calvaria defect model and screening system

OBJECTIVES: The aim of this study was to evaluate the effects of herbal extracts on bone regeneration. Two known samples were screened. MATERIALS AND METHODS: We previously established a rat calvaria defect model using a combination of collagen scaffold and herbal extracts. An 8 mm diameter trephine bur with a low-speed dental hand piece was used to create a circular calvaria defect. The experimental group was divided into 4 classifications: control, collagen matrix, Danshen with collagen, and Ge Gan with collagen. Animals in each group were sacrificed at 4, 6, 8, and 10 weeks after surgery, and bone regeneration ability was evaluated by histological examination. RESULTS: Results revealed that both Danshen and Ge Gan extracts increased bone formation activity when used with collagen matrix. All groups showed almost the same histological findings until 6 weeks. However, after 6 weeks, bone formation activity proceeded differently in each group. In the experimental groups, new bone formation activity was found continuously up to 10 weeks. In the Danshen and Ge Gan groups, grafted materials were still present until 10 weeks after treatment, as evidenced by foreign body reactions showing multinucleated giant cells in chronic inflammatory vascular connective tissue. CONCLUSION: Histological analyses showed that Danshen and Ge Gan extractions increased bone formation activity when used in conjunction with collagen matrix.