Objectives: The main objective of this research was to analyze some selected indigenous wild mushrooms in Arunachal Pradesh, namely, Lactifluus pilosus, Lactifluus piperatus, Lactifluus indovolemus, Lactifluus crocatus, Lactarius hirtipes, Lactarius kesiyae and Lactarius viridinigrellus for their novel anti-oxidant components in two different solvent extracts. Materials and Methods: The antioxidant properties of water and methanol extracts of these mushrooms were determined by the total phenolics and flavonoid content, reducing power capacity, radical scavenging activity by 1,1-diphenyl-2-picrylhydrazyl and (2,2'-azino-bis [3–ethylbenzothiazoline–6–sulfonic acid]) radicals. The quantification of phenolics and flavonoids was carried out by high-performance liquid chromatography (HPLC) using Acclaim C18 column, Dionex Ultimate 3000 liquid chromatograph, and detection was carried out in photodiode array detector. Results: The result showed that the total phenolics and flavonoids of the different extracts of the investigated mushrooms ranged from 3.77 ± 0.57 to 65.88 ± 1.81 mg gallic acid equivalents/100 g dry extract (DE) and 1.98 ± 0.002–12.64 ± 0.08 mg rutin equivalent/100 g DE, respectively. Furthermore, the mushroom extracts exhibited good free radical scavenging capacity. The HPLC experiment of both extracts showed the presence of different phenolic acids and flavonoids such as protocatechuic acid, syringic acid, quercetin, and Kaempferol in various amounts. Conclusion: The wild mushrooms have been studied to analyze their antioxidant property. These mushrooms may be used as functional additives or can be incorporated into our food regime, representing an alternative source of food to prevent damage caused by oxidation in the human body.