Discussion The results showed that variations in the TPC and TFC of different extracts are affected by the polarity of the solvent used and the nature of the phytochemicals dissolved. The fact that extraction solvents with different polarities extract varying amounts of polyphenol and flavonoid compounds from plants is well known [37–40]. This study used a range of extraction solvents, from those with low polarity to those with high polarity, in order to dissolve phytochemicals with similar polarities. The hexane extract (DMH) obtained from using hexane, a low-polarity solvent, had little TPC or TFC because it has very few phytochemicals derived from either polyphenol or flavonoid groups. In contrast, both chloroform and acetone extracts exhibited high TPC and TFC, probably because these extracts contain many compounds of polyphenol and flavonoid groups with polarities similar to those of chloroform and acetone. Previous research on the extraction of differing flavonoid and polyphenol contents and compounds in different solvents in various Dendrobium species supports the present research [37, 41–44]. The types of compounds we identified in D. moniliforme in this study were similar to those identified in this plant in previous studies