This PhD thesis envisages the phytochemical and biological investigation of two important indigenous species of Pakistan. The main objective behind this investigation was to authenticate the folkloric history of these species. Asparagus adscendens Roxb. (A. adscendens), is native to the Himalayas. This plant has been used in the prevention and effective treatment of various forms of cancers. Trillium govanianum Wall. (T. govanianum), is a native species of the Himalayas. In folk medicine the plant has been reported for the treatment of wound healing, sepsis and in various sexual disorder Finely ground roots of A. adscendens and T. govanianum were macerated in methanol and extracted through solid-phase extraction by using gradient solvent system (water: methanol) It was further proceeded for analysis of fingerprint high performance liquid chromatography - photodiode array and highly sensitive liquid chromatographyelectrospray ionization-quadrupole time of flight- mass spectrometry to obtain insights into the possible chemical composition of the fractions, particularly, to have an indication whether they contain phenolic, flavonoids, saponins or spogenin as possible contributors to the significant antioxidant, antimicrobial, antileishmanial and cytotoxic activities of the extracts and its fractions. Reverse phase HPLC-PDA based quantification revealed the presence of significant amount of quercetin, myricetin and kaempferol ranging from 23.31 to 234.23 & 0.221to 0.528 μg/mg DW for A. adscendens and T. govanianum, respectively. Moreover, in this study about 154 compounds have been identified by using both positive and negative ion mode liquid chromatography - mass spectrometry and gas chromatography - mass spectrometry analysis. LCMS analysis of A. adscendens, revealed compounds (4-29) and (30-37) and most of them are biological active e.g. Levoglucosan (C-10), Brugine (C-14) and (C-20) Bergenin. LCMS analysis of T. govanianum identified various biological active saponins and sapogenins e.g. Digoxigenin (C-52), Alliospiroside D (C-53), Hovenoside D(C-55), Pisumsaponin I (C-57), Fistuloside A (C-58), Pitheduloside F (C-60), Durupcoside B (C-61), xii Cyclopassifloside I (C-68), Ophiopogonin D (C-72), Crosatoside B (C-99), Yayoisaponin B (C-107), Protodioscin (C-109), Isoeruboside B (C-111), Phytolaccasaponin B (C-114), Calendasaponin C (C-115), Calendasaponin D (C-116), Azukisaponin IV (C-119), Pseudoprotodioscin (C-121), Polypodoside A (C-122), Agavasaponin C (C-123), Schidigerasaponin B1 (C-124), Dioscin (C-125), Pitheduloside K (C-127), Fistuloside B (C-129) and Ophiopogonin B (C-130). The GC/MS analysis of n-hexane fraction of MeOH extract of the roots of A. adscendens and T. govanianum was performed to get the fatty profile of both extracts. GC/MS analysis revealed the presence of twelve components (C-141 to 155). In current study, all the phytochemical and biological assays were performed on methanolic extract and SPE of A. adscendens and T. govanianum. The total phenolic and flavonoid contents of A. adscendens and T. govanianum in terms of gallic acid and quercetin equivalent per gram dry weight exhibited different levels of significant phenolic and flavonoid contents. Antioxidant assays, including DPPH scavenging activity, total antioxidant capacity and ferric reducing antioxidant power of A. adscendens and T. govanianum exhibited different levels activity, which might be attributed to the presence of phenolic compounds and possible saponins. The MeOH extract and SPE of A. adscendens and T. govanianum exhibited mild antibacterial activity determined by the zone of inhibition (mm diameter) ranges from 7 to 13 mm, against Staphylococcus aureus (NCTC 7508); Bacillus subtilis (NCTC 1604); M. luteus (NCTC 75080); Escherichia coli (ATCC 25922). The antimicrobial potential of both A. adscendens and T. govanianumwas further accessed to determine the minimum inhibitory concentration (MIC) values by using resazurin microtiter assay (REMA), which exhibited considerable level of antibacterial potential against gram-positive bacteria (MIC: 2.5-0.009 mg/mL) than against gram-negative bacteria (MIC: 1.25-2.5 mg/mL). The antifungal potential of A. adscendens and T. govanianum were established against four strains of filamentous fungi. i.e Aspergillus fumigatus FCBP- 66; Mucor species (FCBP-0300); Aspergillus niger (FCBP-0198) and Aspergillus flavus (FCBP0064) showed mild to moderate or weak antifungal activity. Antileishmanial capability of A. adscendens and T. govanianum against Leishmania tropica KWH23 strain were manifested mild to moderate results. xiii Cytotoxicity potential of A. adscendens and T. govanianum were accessed by using brine shrimp lethality assay, protein kinase inhibition assay and in vitro 3-(4,5dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay. The distinguishable protein kinase inhibitory activity against Streptomyces 85E strain with 19± 1.06 mm bald, 9± 0.45mm clear phenotype was observed around the MeOH extract. The MeOH extract of the roots and SPE fractions of A. adscendens and T. govanianum displayed considerable levels of cytotoxicity (79 µg/mL& 14-29 µg/mL respectively) against four human carcinoma cell lines, e.g., breast (MCF7), liver (HepG2), lung (A549), urinary bladder (EJ138) and one non-carcinoma vero (CL81) in the MTT cytotoxicity/viability assay. It is reasonable to assume that the cytotoxicity of MeOH extract and SPE fractions of the roots of A. adscendens and T. govanianum might be, at least partly, owing to the presence of saponins and their aglycones, suggest that these species could be exploited as a potential source of cytotoxic compounds with putative anticancer potential. Among all the SPE of methanolic extracts of both species, which shows promising results against several bio-assays, were subjected to preparative-HPLC for isolation and characterization. Several compounds were isolated and collected through prep-HPLC but only three flavonoids C-156-C-158 (Epimedium C, Basohuoside I and Chrysin) were managed for their full characterization. The structures of all isolated compounds (C-156-C-158) were elucidated by spectroscopic analysis. This is the first report on the occurrence of compounds Epimedium C, Basohuoside I and Chrysin in the genus Asparagus. All isolated compounds exhibited different levels of cytotoxicity against four human carcinoma cell lines, e.g., breast (MCF7), liver (HepG2), lung (A549) and urinary bladder (EJ138) and one non-carcinogenic vero (CL81) cell line, using the in vitro MTT cytotoxicity/viability assay. By keeping in view the IC50 values of isolated compounds ranges from 22-325 (µg/mL) against four human cancer cell lines, molecular docking studies were initiated to identify the binding modes of isolated compounds (C-156 and C-158) and selected identified compounds (Calendasaponin C (C-115), Yayoisaponin B (C-107), Agavasaponin C (C-123), Azukisaponin IV (C-119) and Protodioscin (C-109) with targeted receptors. The selected compounds have shown promising docking result against epithelium growth factor receptor protein. To our best knowledge, this is the first report showing significant phytochemical and biological potential of Asparagus adscendens and Trillium govanianum indigenous to Pakistan.