Essential oils and nutrients constitutes of Kaempferia parviflora rhizome and the activities against plant pathogens

【Objective】 This study was intended to elucidate the chemical composition and relative content of volatile oil from the rhizome of Kaempferia parviflora, determine the contents of various nutrients, and explore the antimicrobial activities of different extracts from the rhizome of K. parviflora. These results provide theoretical basis for the comprehensive development and utilization of K. parviflora resources.【Method】 The volatile oil from rhizome of K. parviflora was extracted by steam distillation and its chemical constituents were analyzed by gas chromatography-mass spectrometry (GC-MS). The composition and contents of protein, crude polysaccharide and trace elements in rhizome of K. parviflora were determined by Kjeldahl method, acid-phenol colorimetric method and microwave digestion-inductively coupled plasma mass spectrometry(ICP-MS) semi-quantitative analysis method, respectively. The amino acid composition and content were determined by ion exchange chromatography with ninhydrin post-column derivatization. The inhibitory activities of different extracts from rhizome of K. parviflora against six bacteria and two fungi were determined by the bacteriostatic zone method and the mycelium growth rate method.【Result】 The yield of volatile oil in rhizome of K. parviflora was 0.14‰. A total of 66 components were identified from the volatile oil of K. parviflora rhizomes, accounting for 94.51% of the total volatile components including olefins, alcohols, aldehydes, ketones and esters. The main components were borneol (13.02%), linalool(12.27%) and 1-methyl-5-1,6-cyclodecadiene(5.42%). The contents of protein and crude polysaccharide in rhizome of K. parviflora were 3.83 g/100 g and 3.33 g/100 g respectively. The total of 16 amino acids was 2.94 g/100 g, among which the content of arginine(ARG) was the highest with 0.61 g/100 g, followed by aspartic acid(ASP) with 0.46 g/100 g. A total of 28 trace elements were detected in rhizome of K. parviflora, of which the content of potassium was the highest(3270 mg/kg), followed by magnesium(813 mg/kg), calcium (289 mg/kg), manganese (146 mg/kg) and aluminium(135 mg/kg). The contents of other trace elements were all below 80 mg/kg. The ethyl acetate layer extract from rhizome of K. parviflora showed the best antibacterial activity, and the petroleum ether layer extract showed the strongest inhibitory activity against Pesudocryphonectria elaeocarpicola with the half-maximal effect concentration (EC₅₀) value was 14.11 μg/mL.【Conclusion】 The main components of volatile oil in rhizome of K. parviflora are borneol and linalool, and the rhizome contains protein, amino acid and trace elements. The ethyl acetate layer extract of rhizome of K. parviflora has good antibacterial activity, and the petroleum ether layer extract has obvious antifugal effect against P. elaeocarpicola. K. parviflora has important development and application values as a new understory resource plant.