Evaluation of Microwave-Assisted Extraction Method for Preparation and Assessment of Thai Herbal Medicine Oral Tablets With Enriched Phytochemical Compounds

AAPS PharmSciTech. 2021 Jun 2;22(5):167. doi: 10.1208/s12249-021-02052-4.


In developing countries, populations have employed herbal medicines for primary health care because they are believed to be more appropriate to the human body and have less side effects than chemically synthesized drugs. The present study aimed to develop and evaluate herbal tablets incorporated with a Thai traditional medicinal extract, U-pa-ri-waat (URW), using microwave-assisted extraction (MAE). The extraction efficiency for URW using MAE and traditional solvent extraction was compared based on the percent yield after spray drying. URW tablets were prepared using the dry granulation method. The optimized products were assessed using standard characterization methods based on the United States and British Pharmacopeias. DPPH and ABTS radical scavenging assays were performed to analyze the antioxidant capacity of the microwave-assisted extracts. The results revealed that the flowability of the dry granule with added maltodextrin was improved compared to a granule without additives, as indicated by an angle of repose of 33.69 ± 2.0°, a compressibility index of 15.38 ± 0.66, and a Hausner's ratio of 1.18 ± 0.06. The resulting formulation produced flat tablets with uniform weight variation, hardness, thickness, friability, and optimum disintegration time. The URW extracts showed antioxidant activity and MAE with maltodextrin carrier displayed the strongest DPPH and ABTS radical activities with IC50 values of 1.60 ± 0.02 μg/mL and 4.02 ± 0.24 μg/mL, respectively. The URW tablet formulation passed the quality control tests. Storage of the formulation tablets for 90 days under accelerated conditions had minimal effects on tablet characteristics.

Keywords: antioxidant activity; dry granulation; herbal formulation; medicinal plants; microwave-assisted extraction.

MeSH terms

  • Administration, Oral
  • Antioxidants / administration & dosage
  • Antioxidants / chemical synthesis
  • Antioxidants / pharmacokinetics
  • Chemistry, Pharmaceutical / methods*
  • Drug Evaluation, Preclinical / methods
  • Free Radical Scavengers / administration & dosage
  • Free Radical Scavengers / chemical synthesis
  • Free Radical Scavengers / pharmacokinetics
  • Herbal Medicine / methods
  • Humans
  • Microwaves*
  • Phytochemicals / administration & dosage
  • Phytochemicals / chemical synthesis*
  • Phytochemicals / pharmacokinetics
  • Plant Preparations / administration & dosage
  • Plant Preparations / chemical synthesis*
  • Plant Preparations / pharmacokinetics
  • Tablets
  • Thailand


  • Antioxidants
  • Free Radical Scavengers
  • Phytochemicals
  • Plant Preparations
  • Tablets