A Review of Cytotoxic Plants of the Indian Subcontinent and a Broad-Spectrum Analysis of Their Bioactive Compounds

Abstract

Cancer or uncontrolled cell proliferation is a major health issue worldwide and is the second leading cause of deaths globally. The high mortality rate and toxicity associated with cancer chemotherapy or radiation therapy have encouraged the investigation of complementary and alternative treatment methods, such as plant-based drugs. Moreover, over 60% of the anti-cancer drugs are molecules derived from plants or their synthetic derivatives. Therefore, in the present review, an attempt has been made to summarize the cytotoxic plants available in the Indian subcontinent along with a description of their bio-active components. The review covers 99 plants of 57 families as well as over 110 isolated bioactive cytotoxic compounds, amongst which at least 20 are new compounds. Among the reported phytoconstituents, artemisinin, lupeol, curcumin, and quercetin are under clinical trials, while brazilin, catechin, ursolic acid, β-sitosterol, and myricetin are under pharmacokinetic development. However, for the remaining compounds, there is little or no information available. Therefore, further investigations are warranted on these subcontinent medicinal plants as an important source of novel cytotoxic agents.

Biocatalysis in the Chemistry of Lupane Triterpenoids

“…There are many other plant species that produce betulin ( 8 ) in low amounts, but to the best of our knowledge, none of them are used as important sources of it. Lupeol ( 9 ) is another lupane triterpene naturally occurring in plants; however, its quantities are usually lower than the quantities of 5 or 8, and it is usually obtained as a side-product of extractions of other triterpenes [ 49 , 50 , 51 ]. A basic summary of the main lupane triterpenoid sources is in Table 1 .…”

“… Methods of synthesis of betulinic acid [ 47 , 48 , 49 , 50 , 51 , 52 ]. Reagents and conditions: (i) chromium(VI) oxide; sulfuric acid, and acetone, H 2 O; (ii) sodium tetrahydroborate and isopropyl alcohol; (iii) 4-acetylamino-2,2,6,6-tetramethylpiperidine-N-oxyl, sodium chlorite, tetrabutylammomium bromide, sodium hypochlorite, and phosphate buffer at 50 °C; (iv) 4-acetylamino-2,2,6,6-tetramethylpiperidine-N-oxyl, tetrabutylammomium bromide, sodium hypochlorite, and phosphate buffer (pH = 7.6) at 50 °C; (v) BAIB, TEMPO, NaH 2 PO 4 , NaClO 2 , 2-methyl-2-butene, BuOAc, water, and t-BuOH at 20 °C for 6 h; (vi) 2,6,6-tetramethyl piperidine-N-oxyl, tetrabutylammomium bromide, and sodium hypochlorite in phosphate buffer with dichloromethane for 6 h with pH = 6.8; (vii) sodium dihydrogenphosphate, sodium permanganate, DCM, water, and tert-butyl alcohol at 25 °C for 3 h; (viii) K 2 CO 3 and MeOH for 24 h; and (ix) KOH and MeOH with heating for 3 h. …”

Anti-Syncytium (MC99+1A2) and Anti-Bacterial Activities from Twigs and Stems of Ficus dubia

“…From Table 3, the extracts and pure compounds of Ficus dubia were inactive with all strains of the human cancer cell line. Although crude extracts and compounds from the twigs and stems of Ficus dubia do not have cytotoxicity, but the root, leaf and fruits of another Ficus species have good cytotoxicity, such as Ficus pseudopalma Blanco [14], Ficus beecheyana [15], Ficus carica [15], Ficus racemosa [15] and Ficus hispida Linn [16]. These results revealed that the extract and compounds of twigs and stems of Ficus dubia were selective in anti-HIV virus activity.…”

Aquilaria malaccensis Lam. Thymelaeaceae

“…Anticancer and cytotoxic: Aqueous leaf extracts inhibit the cyclophosphamideinduced toxicity in reproductive systems in male rats (Abdul Razak et al 2019). Anticancer activities have been reported on HCT116, DLA, and EAC cancer cell lines (Mazumder et al 2020). The stem bark shows anticancer properties against P388 lymphocytic leukemia cells and HCT116 colorectal cancer cell lines (Gunasekera et al 1981;Hashim et al 2016;Ibrahim et al 2011).…”