Synergistic effect and different toxicities of adjuvant components of Realgar–Indigo Naturalis formula

Dissection of scientific compatibility of Chinese medicinal formula Realgar-Indigo naturalis as an effective treatment for promyelocytic leukemia from the perspective of toxicology

ETHNOPHARMACOLOGICAL RELEVANCE

Realgar-Indigo naturalis formula (RIF), a first-line drug for the treatment of acute promyelocytic leukemia (APL),is also a TCM formula entirely designed based on TCM theories. There have been studies that explain the scientific connotation of the compatibility of RIF from the perspective of pharmacodynamics. However, as one of the arsenic-containing preparations, the safety of realgar is widely concerned, and there has not been systematic studies to explain the scientific connotation of RIF from the perspective of toxicology.

AIM OF THIS STUDY

Dissection of scientific compatibility of Chinese medicinal formula Realgar-Indigo naturalis as an effective treatment for promyelocytic leukemia from the perspective of toxicology.

MATERIALS AND METHODS

We used normal mice and an APL model to explore (i) the effects of different components on intestinal permeability, (ii) the changes in intestinal flora, and (iii) toxic effects. At the same time, a bionic extraction method was used to study the effects of different components on the dissolution of soluble arsenic in realgar under the acidic environment in the stomach and the alkaline environment in the intestinal tract.

RESULTS

Salvia miltiorrhiza Bunge can repair the intestinal mucosal barrier, maintain the homeostasis of intestinal flora, intervene in the dissolution process of realgar, reverse the increase in intestinal permeability and the disturbance of intestinal flora caused by realgar, and reduce toxicity.

CONCLUSION

From the perspective of toxicology, we propose new insights into the definition of the roles of each component in the RIF formula, namely realgar is the monarch, Indigo naturalis is the minister, Salvia miltiorrhiza Bungeis the assistant.

Compatibility of Niuhuang Jiedu Tablets Results in Attenuated Arsenic Bioaccumulation and Consequent Protection against Realgar-Induced Toxicity in Mice

Niuhuang Jiedu Tablets (NJT) is a popular over-the-counter traditional Chinese medicine (TCM) preparation. It is composed of realgar (As₂S₂) and seven other TCMs. The safety of NJT is of growing concern because arsenic (As) is carcinogenic to humans. The toxicity of realgar in vivo can mainly be attributed to the absorbed and accumulated As. This study investigated the correlation between the detoxification effects of the other TCMs in NJT on realgar and their influences on arsenic accumulation of realgar in mice. Histopathological examination, clinical biochemical test, and metabolic profiling analysis were used to evaluate the toxicity of realgar. The concentration of arsenic in mice whole blood as the hazard indicator was determined by inductively coupled plasma mass spectrometry (ICP-MS). The compatibility of NJT could decrease arsenic bioaccumulation of realgar in mice whole blood and consequently reduce the toxicity of realgar, which could be considered as one detoxification mechanism to realgar in NJT. The combination of Rhei Radix et Rhizoma, Scutellariae Radix, Platycodonis Radix, and Glycyrrhizae Radix et Rhizoma exhibited almost the same effects as NJT in regulating the serum biochemical parameters and metabolic profiles disturbed by realgar and in reducing arsenic accumulation of realgar in mice whole blood.

Development of arsenic trioxide sustained-release pellets for reducing toxicity and improving compliance

Arsenic trioxide (ATO) is first-line drug for acute promyelocytic leukemia. Clinically, the continuously slow intravenous infusion is adopted to maintain effective blood concentration and reduce toxic effects, but it causes poor patient' compliance for a considerable infusion period. To overcome these disadvantages, we developed an oral ATO sustained-release preparation which was constructed via the ATO core pellets prepared by extrusion spheronization and followed by a coating membrane by fluid-bed technology. The prepared coated pellets displayed a round surface and uniform particle size. All in vitro release profiles of ATO pellets in different pH media and rotation speeds had no statistical difference. Importantly, the coated pellets can release completely in 12 h without obvious burst release. There was no distinct change in appearance and release behaviors in stability experiments. In vivo pharmacokinetics was studied by one-time intragastric administration of rats. Compared with free drug, the AUC_0-∞ of the ATO coated pellets was 2.3-fold higher, indicating the oral bioavailability was significantly increased. C_max decreased by about a half and T_max extended about 15 h. In particularly, the ATO level at 96 h only decreased about 20% of C_max , suggesting that the ATO sustained-release preparation could not only decrease the peak concentration, but also maintain a relatively constant blood concentration for a long period. Further, the in vivo absorption could be well predicted by in vitro release experiments. Therefore, the ATO sustained-release preparation formulated by the mature preparation technology, possessing satisfactory stability and improving bioavailability, had great application potentials for industrialization.

Arsenic Bioaccessibility of Realgar Influenced by the Other Traditional Chinese Medicines in Niuhuang Jiedu Tablet and the Roles of Gut Microbiota

Niuhuang Jiedu tablet (NJT), a realgar (As2S2) containing Traditional Chinese Medicine (TCM), is a well-known formula. The safety of NJT is of growing concern since arsenic (As) is considered as one of the most toxic elements. NJT was demonstrated to be safer than realgar by our previous experiments and some other studies. The toxicity of realgar has been shown to be related to the amount of soluble or bioaccessible arsenic. In this study, the influences of the other TCMs in NJT on the bioaccessibility of arsenic from realgar, and the roles of gut microbiota during this process were investigated in vitro. Results showed that Dahuang (Rhei Radix et Rhizoma), Huangqin (Scutellariae Radix), Jiegeng (Platycodonis Radix), and Gancao (Glycyrrhizae Radix et Rhizoma) could significantly reduce the bioaccessibility of arsenic from realgar in artificial gastrointestinal fluids. Gut microbiota played an important role in decreasing the bioaccessibility of realgar because it was demonstrated to be able to absorb the soluble arsenic from realgar in the incubation medium. Dahuang, Huangqin, and Jiegeng could modulate the gut microbiota to enhance its arsenic absorption activity.