•Aconitine alkaloids were excreted mainly through feces.•Fecal excretion of aconitine alkaloids might be related to high expression of MRAP 2.•The combination of Mahuang and Fuzi may increases the risk of drug accumulation.Herba Ephedrae-Radix Aconiti Lateralis, composed of Ephedrae (Mahuang in Chinese) and Radix Aconiti Lateralis (Fuzi in Chinese), is a classical herbal combination proven to be effective in treating common cold, asthma, and rheumatoid arthritis. Alkaloids, bioactive components of the herbal extract, have been associated with many side effects. Nine alkaloids, including norephedrine, norpseudoephedrine, ephedrine, pseudoephedrine, methylephedrine, hypaconitine, benzoylaconine, benzoylmesaconine and benzoylhypaconine, were simultaneously quantified within 14.5 min, by a validated ultra-performance liquid chromatography-tandem mass spectrometry method in various rat tissues, urine, and feces after oral administration of Mahuang-Fuzi and single-herb extracts. The results indicated that the alkaloids were widely distributed in the heart, liver, spleen, lung, kidney, and brain. Lower bioavailability and higher clearance of some alkaloids were observed for the herbal combination, but hypaconitine showed a longer residence time and lower clearance. Elimination kinetics demonstrated that ephedra and aconitum alkaloids were mainly excreted in urine and feces, respectively. The tissue distribution and excretion of ephedra and aconitum alkaloids are comprehensively reported for the first time for the Mahuang-Fuzi combination. Compared with single-herb extracts, lower extraction efficiencies of alkaloids in vitro were observed which may result in their lower intake. However, the combination showed a prolonged residence time and delayed elimination of aconitum alkaloids, which increases the risk of drug accumulation. The study demonstrated potential risks of intoxication with aconitum alkaloids, associated with the use of Fuzi in combination with Mahuang. Mahuang-Fuzi is a classical combination used in clinics, further investigation is needed.

To assess the antinociceptive and anti-inflammatory properties of the aqueous extract of Armadillidium vulgare (AV).The antinociceptive effect of AV (400, 600 and 800 mg/kg) was investigated in mice using the acetic acid-induced writhing, formalin-induced nociceptive, and hot plate tests. Phlogogen-induced paw edema using carrageenan, dextran, or compound 48/80 as phlogogen was used as inflammatory models to evaluate AV's anti-inflammatory effect. Additionally, the bioactive substances glucosamine (GLcN) and taurine in AV were determined using high-performance liquid chromatography.Oral treatment of the mice with AV (600 and 800 mg/kg) significantly reduced the number of writhes in the acetic acid-induced writhing test (P<0.01) but not the hot plate test (P>0.05). All doses tested significantly inhibited paw-withdrawal during the second phase of the formalin-induced nociceptive model (P<0.01). AV demonstrated a strong anti-inflammatory effect in all those inflammatory models (P<0.05).AV has antinociceptive and anti-inflammatory effects, providing scientific evidence of the efficacy of its traditional use in pain treatment. Furthermore, GLcN and taurine contribute, at least in part, to the anti-inflammatory activity of AV.

•A simple LC–MS/MS method was developed and validated for bioanalysis of the compounds.•Pharmacokinetics study of amygdalin and its epimers were reported here for the first time.•Stereo-selective metabolism of amygdalin occurred in vivo.•The study illustrated the rationale behind the preferred use of the combination of MX.The Mahuang–Xingren herb-pair (MX), the combination of Herba Ephedrae (Mahuang in Chinese) and Semen Armeniacae Amarum (Xingren in Chinese), is a classical combination used in traditional Chinese Medicine to treat asthma and bronchitis. A simple and reliable ultra-performance liquid chromatography-tandem mass spectrometry method was developed to simultaneously quantify and compare the pharmacokinetics of 5 ephedra alkaloids and epimers of amygdalin and prunasin in rat plasma after oral administration of Mahuang, Xingren, and MX aqueous extracts. Samples were pretreated by a single-step protein precipitation with acetonitrile, and diphenhydramine hydrochloride and puerarin were used as internal standards. Pharmacokinetic parameters were investigated using DAS 3.2.2 (Mathematical Pharmacology Professional Committee of China, Shanghai, China). The validated method demonstrated adequate sensitivity, selectivity, and process efficiency for the bioanalysis of 8 compounds, including 3 pairs of epimers. MX administration improved the bioavailability of amygdalin and prunasin. Furthermore, MX facilitated intake of lower doses of ephedra alkaloids and increased elimination rates in comparison with Mahuang alone. These results illustrate the rationale behind the preferred use of the combination of Mahuang and Xingren. To our knowledge, this is the first report of stereo-selective metabolism of amygdalin. Further, the metabolic mechanism underlying this phenomenon merits future research attention.