Table 1.

Important natural products derived from plant and microbial sources in the last few decades with their therapeutic indications and probable mechanism of actions.

Name of the Natural Compound	Botanical Source	Chemical Structure	Therapeutic Indication/Activities	Mechanism of Action	References
Drugs Derived from Plant Sources
Arglabin	Artemisia glabella		Anti-tumor	Inhibition of farnesyl transferase	[21,22]
Artemisinin	Artemisia annua L.		Treatment of malaria	Free radical formation that alkylate essential malarial proteins	[23]
Cannabidiol	Cannabis sativa L		Anti-epileptic, anxiolytic, antipsychotic, and anticancer	Modulation of CB1, CB2, 5HT1A receptors in the CNS	[24]
Capsaicin	Capsicum annum L.; C. minimum Mill.		Chronic pain syndromes such as postherpetic neuralgia and musculoskeletal pain	Activates Transient receptor potential vanilloid 1 (TRPV1) in sensory nerves	[25]
Colchicine	Colchicum spp.		Gout	Prevents microtubule assembly and hence modulate multiple pro- and anti-inflammatory pathways	[26]
Curcumin	Curcuma longa L. (Turmeric)		Antioxidant, anti-inflammatory, arthritis, metabolic syndrome and pain	Inhibition of NF-kB; scavenge reactive oxygen and nitrogen species; modulates the activities of GSH, catalase and SOD	[27]
Epigallocatechin-3-O-gallate (EGCG)	Camellia sinensis L. (Green tea)		Anti-viral against a diverse family of DNA and RNA viruses; antibacterial and antifungal activities. Anticancer, anti-inflammatory and anti-diabetic activities	Alter or damage viral particle, primary target is viral membrane; disruption of lipid layer in bacterial cell wall; inhibits dihydrofolate reductase. Modulation of ROS production and inhibition of NF-kB signaling responsible for anticancer activity	[28,29]
Galantamine	Galanthus caucasicus Grossh.		Dementia associated with Alzheimer’s disease	Reversible acetylcholinesterase inhibitor; modulation nicotinic acetylcholine receptor (nAChRs)	[30]
Genistein	Genista tinctoria L.		Anticancer, Alzheimer’s disease	Protein-tyrosine kinase inhibition, induction of apoptosis, cell cycle arrest, antimetastatic and antiangiogenic activity, antioxidant	[31]
Gossypol	Gossypium hirsutum L. (Cotton plant); Thespesia populnea		Anti-infertility/male contraceptive, Anticancer, antiviral, antimicrobial, antioxidant activities	Inhibit sperm production and motility; Bcl-2 inhibition; DNA polymerase and topoisomerase II inhibition; induce apoptosis	[32]
Ingenol mebutate	Euphorbia peplus L.		Actinic keratosis	Dual mechanism, Inducer of cell death necrosis and local pro-inflammatory response	[33]
β-Lapachone	Tabebuia avellanedae (Lapacho tree)		Variety of cancers, especially solid tumors, anti-trypanosoma, antimicrobial and antimalarial activities	Anticancer activity through formation of ROS in NQO1-positive cells, topoisomerase inhibition, mTOR pathway modulator	[34,35]
Masoprocol	Larrea tridentate		Antineoplastic agent used in cancer chemotherapy	5-Lipoxygenase inhibition	[36]
Omacetaxine mepesuccinate (Homoharringtonine)	Cephalotaxus harringtonia; C. fortune		Anticancer agent; mainly chronic myeloid leukemia (CML)	Protein synthesis inhibition (prevent peptide elongation)	[37]
Paclitaxel	Taxus brevifolia Nutt.		Cancer chemotherapy	Mitotic inhibitor	[36,38]
Podophyllotoxin	Podophyllum emodi Wall. and P. peltatum L.		Antitumor	Polymerization of tubulin resulting in cell cycle arrest and suppress the formation of mitotic spindles microtubules	[39]
Quercetin	Many sources including Allium cepa L.; Morus alba; Camellia sinensis; Moringa oleifera; Centella asiatica etc.		Antioxidant, anti-inflammatory, anticancer, cardiovascular protection; Alzheimer’s disease; anti-ulcer; antimicrobial; antiallergic	Inhibits cyclooxygenase and lipoxygenase; inhibits platelet aggregation; inhibit gastric secretion and lipid peroxidation; ROS generation and MicroRNA 21 elevation	[40]
Resveratrol	Vitis vinifera L		Chemopreventive and chemotherapeutic in different types of cancer. Also used as antidiabetic, in cardiovascular complications, metabolic syndromes, antioxidant.	Modulation of multiple molecular pathways involved in cancer and xenobiotic metabolism; reduce oxidative stress and inflammation; cell proliferation arrest; induce apoptosis	[34]
Drugs Derived from Microbial Sources
Teixobactin	Eleftheria terrace	N-[N-Methyl-D-Phe-Ile-Ser-D-Gln-D-alle-Ile-Ser-]cyclo[D-Thr-Ala-[3-(2-iminoimid-azolidine-4 beta-yl)-Ala-]Ile-]	Antibacterial agent active against various gram-positive bacterial including vacomycin resistant enterococci and methicillin-resistant S. aureus	Inhibition of bacterial cell-wall sybthesis by binging to the synthesis building blocks lipid-II and lipid-III	[41]
Lodopyridone	Saccharomonospora sp.		Anticancer	Cytotoxic to HCT-116 human colon cancer cells	[42]
Salinosporamide A	Salinospora tropica		Anticancer	Inhibition of 20S Proteasome	[43]
Platensimycin	Streptomyces platensis		Antibiotic, active against various Gram-positive bacteria including resistant strains	Inhibition of fatty acid synthesis in cell membrane through inhibition of β-ketoacy synthases I/II (FabF/B)	[44]
Platencin	Streptomyces platensis		Antibiotic, active against various Gram-positive bacteria including resistant strains	Inhibition of fatty acid synthesis in cell membrane through inhibition of β-ketoacy synthases I/II (FabF/B)	[44]
Cryptophycin	Cyanobacteria Nostoc sp.		Anticancer	Inhibiotion of cell division by depletion of microtubule through interaction with tubulin	[45]
Daptomycin	Streptomyces roseosporus	-	Systemic and life-threatening infection caused Gram-positive bacteria	Disruption of bacterial cell-membrane function	[46]
Retapamulin	Pleurotus mutilins		Antibacterial used to treat topical skin infection impetigo	Inhibition of bacterial protein synthesis by binding to 50s ribosome	[47]