A new approach for identification of medicinal almonds by fourier transform infrared spectroscopy and systematic clustering of characteristic peaks

Medicinal almonds have been used for over 2 000 years and its clinical efficacy includes relieving cough and asthma. The domestic market in China is flooded with different kinds of dried almonds, such as bitter almond (Armeniacae Semen Amarum, AAS), sweet almond (Armeniacae Semen Dulce, ADS), salted almond (Armeniacae Semen Salsa, ASS), and their sulfur-fumigating products (Armeniacae Semen Sulphur Fumabat, ASFS). Wide varieties of almonds may lead to uncertain efficacy, aberrant quality, and even increased safety risk. However, the authentication method for medicinal almonds has not been reported, although imposters may lead to ineffective medical response. In the present study, Fourier transform infrared spectroscopy (FTIR) and the 2-dimensional infrared (2D-IR) spectroscopy were used to identify different almonds, which were extracted with different solvents including water, methanol, ethanol, chloroform and ethyl acetate, respectively. A new simple FTIR method was developed in the present study. According to the gradient solvent polarity, a new 2D IR method was first developed, and the commodities of almonds in China were analyzed by using the FTIR spectroscopy supported by hierarchical clustering of characteristic peaks. Moreover, 5-hydroxymethyl-2-furfural could be used as a detection index and control target in the quality control of medicinal almonds.

Stereoselective metabolism of amygdalin-based study of detoxification of Semen Armeniacae Amarum in the Herba Ephedrae-Semen Armeniacae Amarum herb pair

ETHNOPHARMACOLOGICAL RELEVANCE

The Mahuang-Xingren (MX) herb pair, the combination of Herba Ephedrae (Mahuang in Chinese) and Semen Armeniacae Amarum (Xingren in Chinese), is a core component of traditional Chinese medicine formulations used to treat asthma and bronchitis. Although Xingren is considered to be toxic, MX is widely used in the clinic and has few adverse effects. The mechanism underlying detoxification of Xingren by Mahuang in MX remains unknown and merits investigation.

AIM OF THE STUDY

To determine the mechanism underlying detoxification of Xingren by Mahuang in MX.

MATERIALS AND METHODS

Acute toxic effects were evaluated in mice after oral administration of Mahuang, Xingren, and MX aqueous extracts. Synergism, additivity, and antagonism were quantified by determining the CI (combination index) and DRI (dose-reduction index), which were calculated by the median effect method. High performance liquid chromatography analysis of bioactive compounds (ephedrine, pseudoephedrine and amygdalin) in aqueous extracts and data from previous pharmacokinetic studies in rats were combined to explore the potential mechanism of toxicity antagonism by the components of MX. Moreover, the cytotoxic effects of amygdalin and amygdalin activated by β-glucosidase (including different proportions of l-amygdalin and d-amygdalin) were also investigated.

RESULTS

Mahuang prevented and antagonized the acute toxicity of Xingren and allowed escalation of the Xingren dose. Pearson correlation analysis indicated that the proportion of d-amygdalin was closely correlated with the antagonism of Xingren toxicity. The antagonism of its acute toxicity was primarily attributed to stereoselective metabolism of amygdalin. Interestingly, the process was facilitated by Mahuang, which led to reduced levels of the d-prunasin in vivo and thus reduced toxicity. Furthermore, the mechanism was also evaluated by testing the cytotoxicity of amygdalin. Metabolism of d-amygdalin was a major cause of cytotoxicity and no stereoselective metabolism occurred in culture medium.

CONCLUSIONS

A comprehensive study of Xingren detoxification in the context of the MX combination suggested that stereoselective metabolism of amygdalin facilitated by Mahuang may be the crucial mechanism underlying detoxification of Xingren in the MX combination. Therefore, Mahuang acts to enhance and control the effects of Xingren in the MX combination. These results illustrate the rationale behind the combination of Mahuang and Xingren.

Concurrent quantification and comparative pharmacokinetic analysis of bioactive compounds in the Herba Ephedrae-Semen Armeniacae Amarum herb pair

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.