Archive for category Herbal Medicine'

Taxol (Paclitaxel) and Cancer Chemotherapy

Taxol is an antineoplastic agent. This compound, first isolated from the bark of the Western yew tree in 1971, exhibits unique pharmacological actions as an inhibitor of mitosis, differing from the vinca alkaloids and colchicine derivatives in that it promotes rather than inhibits microtubule formation. Following its introduction into clinical trial, the drug was approved for treatment of cisplatin-refractory ovarian cancer in 1992 and has promising activity against cancers of the breast, lung, esophagus, and head and neck. Malignant neoplastic diseases may be treated by various approaches: surgery, radiation therapy, immunotherapy, or chemotherapy, or a combination of these. The extent of a malignant disease (staging) should be ascertained in order to plan an effective therapeutic intervention. Plants have antineoplastic activities. A significant portion of the product derived from plants serve either as protective agents against various pathogens (e.g., insects, fungi, or bacteria) or growth regulatory molecules (e.g., hormonelike substances that stimulate or inhibit cell division and morphogenesis). Chemical Groups Of Natural Products With Anticancer Properties Cancer Chemotherapy Before discussing the specific Read more […]

Chemical Groups Of Natural Products With Anticancer Properties

Plant-derived natural products with documented anticancer and antitumor properties can be classified into the following chemical groups (): • Aldehydes • Alkaloids • Flavonoids • Glycosides • Lignans • Lipids • Quinones • Phenols and derivatives • Polysaccharides • Proteins • Terpenoids Aldehydes are volatile substances found (along with alcohols, ketones, and esters) in minute amounts and contributing to the formation of odor and flavor of plant parts. Plants containing aldehydes with anticancer properties include the following: • Cinnamomum cassia • Mondia whitei • Rhus vulgaris • Sclerocarya caffra Alkaloids are weak bases, capable of forming salts, which are commonly extracted form tissues with an acidic, aqueous solvent. Alternatively, free bases can be extracted with organic solvents. Plants containing alkaloids with anticancer properties include the following: Aconitum napellus Acronychia baueri, A. haplophylla Annona purpurea Brucea antidysenterica Calycodendron milnei Cassia leptophylla Chamaecyparis sp. Chelidonium autumnale Ervatamia microphylla Eurycoma longifolia Fagara macrophylla Nauclea orientalis Psychotria Read more […]

Alkylating Agents

The alkylating agents exert their antineoplastic actions by generating highly reactive carbonium ion intermediates that form a covalent linkage with various nucleophilic components on both proteins and DNA. The 7 position of the purine base guanine is particularly susceptible to alkylation, resulting in miscoding, depurination, or ring cleavage. Bifunctional alkylating agents are able to cross-link either two nucleic acid molecules or one protein and one nucleic acid molecule. Although these agents are very active from a therapeutic perspective, they are also notorious for their tendency to cause carcinogenesis and mutagenesis. Alkylating agents that have a nonspecific effect on the cell-cycle phase are the most cytotoxic to rapidly proliferating tissues. Nitrogen Mustards The activity of nitrogen mustards depends on the presence of a bis-(2-chloroethyl) grouping: CH2—CH2C1 | N | CH2—CH2C1 This is present in mechlorethamine (Mustargen), which is used in patients with Hodgkin’s disease and other lymphomas, usually in combination with other drugs, such as in MOPP therapy (mechlorethamine, Oncovin [vincristine], procarbazine, andprednisone). It may cause bone marrow depression. Chlorambucil Chlorambucil Read more […]


Antimetabolites are structural analogues of naturally occurring compounds and function as fraudulent substances for vital biochemical reactions. Folic Acid Analogues Methotrexate (Amethopterin) is a folic acid antagonist that binds to dihydrofolate reductase, thus interfering with the synthesis of the active cofactor tetrahydrofolic acid, which is necessary for the synthesis of thymidylate, purine nucleotides, and the amino acids serine and methionine. Methotrexate is used for the following types of cancer: • Acute lymphoid leukemia: During the initial phase, vincristine and prednisone are used. Methotrexate and mercaptopurine are used for maintenance therapy. In addition, methotrexate is given intrathecally, with or without radiotherapy, to prevent meningeal leukemia. • Diffuse histiocytic lymphoma: Cyclophosphamide, vincristine, methotrexate, and cytarabine (COMA). • Mycosis fungoides: Methotrexate. • Squamous cell, large-cell anaplastic, and adenocarcinoma: Doxorubicin and cyclophosphamide, or methotrexate. • Head and neck squamous cell: Qi-platinum and bleomycin, or methotrexate. • Choriocarcinoma: Methotrexate. Tumor cells acquire resistance to methotrexate as the result of several Read more […]

Taxol and Cancer Chemotherapy: Natural Products

Vinca Alkaloids The vinca alkaloids (vinblastine, vincristine, and vindesine), which bind to tubulin, block mitosis with metaphase arrest. Vinca alkaloids are used for the following types of cancer: • Acute lymphoid leukemia: In the induction phase, vincristine is used with prednisone. • Acute myelomonocytic or monocytic leukemia: Cytarabine, vineristine, and prednisone. • Hodgkin’s disease: Mechlorethamine, Oncovin (vincristine), procarbazine, and prednisone (MOPP). • Nodular lymphoma: Cyclophosphamide, Oncovin (vincristine), and prednisone (CVP). • Diffuse histiocytic lymphoma: Cyclophosphamide, Adriamycin (doxorubicin), vincristine, and prednisone (CHOP); bleomycin, Adriamycin (doxorubicin), cyclophosphamide, Oncovin (vincristine), and prednisone (BACOP); or cyclophosphamide, Oncovin (vincristine), methotrexate, and cytarabine (COMA). • Wilms’ tumor: Dactinomycin and vincristine. • Ewing’s sarcoma: Cyclophosphamide, dactinomycin, or vincristine. • Embryonal rhabdomyosarcoma: Cyclophosphamide, dactinomycin, or vincristine. • Bronchogenic carcinoma: Doxorubicin, cyclophosphamide, and vincristine. The chief toxicity associated with vinblastine use is bone marrow depression. Read more […]

List of Plants by Scientific Name (Singapore)

Scientific Name Common Name Abrus precatorius Rosary Pea, Indian Licorice, Precatory Bean Adiantum capillus-veneris Black Maidenhair Fern, Southern Maidenhair Fern, Venus Hair Fern Allamanda cathartica Allamanda, Common Allamanda, Golden Trumpet Aloe vera Aloe, Lidah Buaya Andrographis paniculata Hempedu Bumi, Sambiloto, Chuan Xin Lian Ardisia elliptica Mata Pelanduk/Ayam, Sea-Shore Ardisia, Shoebutton Ardisia Areca catechu Betel Nut Palm, Areca Nut, Pinang Asplenium nidus Bird’s Nest Fern Aster tataricus Tatarian Aster, Tatarian Daisy Azadirachta indica Neem Barringtonia asiatica Beach Barringtonia, Fish-Killer Tree, Putat Laut Barringtonia racemosa Putat Kampong, Samundrapandu Bauhinia purpurea Butterfly Tree Bixa orellana Annatto, Lipstick Tree Calophyllum inophyllum Indian Laurel, Penaga Laut, Borneo Mahogany Cananga odorata Kenanga, Ylang-Ylang Capsicum annuum Chilli, Red Pepper Cassia fistula Golden Shower Tree, Indian Laburnum, Purging Cassia Catharanthus roseus Madagascar Periwinkle, Rose Periwinkle Celosia Read more […]

Sex Herbs

The following herbs are used to improve sexual function: • Anise imitates the female hormone estrogen, increasing sexual intensity and satisfaction • Epimedium, a Chinese herb, has a testosterone-like substance and enhances a woman’s sexual desire • Fenugreek augments breast size and is used to elevate sex drive • Fennel prolongs orgasm, allowing men to enjoy sex for a longer period of time • Guarana seed tea has aphrodisiac effect • Quebracho (in South America) and Sheng Jing (in China) are used in male infertility and erectile dysfunction (impotence) Erectile dysfunction (ED) is a condition defined by the inability to attain or maintain penile erection sufficient for satisfactory sexual intercourse. In 1995, it was estimated that approximately 152 million men worldwide suffered from erectile dysfunction, with projections for 2025 growing to a prevalence of 322 million affected men. In the past, erectile dysfunction was believed to be caused by nonspecific psychological causes; however, in the past two decades, the majority of cases have been attributed to an organic etiology. Although erectile dysfunction patients can have a number of medical conditions, organic erectile dysfunction Read more […]

Normal Sexual Function

Penile erection is initiated by neuropsychological stimuli that ultimately produce vasodilation of the sinusoidal spaces and arteries within the paired corpora cavernosa. Erection is normally preceded by sexual desire (or libido), which is regulated in part by androgen-dependent psychological factors. Although nocturnal and diurnal spontaneous erections are suppressed in men with androgen deficiency, erections may continue for long periods in response to erotic stimuli. Thus, the continuing action of testicular androgens appears to be required for normal libido but not for the erectile mechanism itself. The penis is innervated by sympathetic, parasympathetic, and somatic fibers. Somatic fibers in the dorsal nerve of the penis form the afferent limb of the erectile reflex by transmitting sensory impulses from the penile skin and glans to the S2-S4 dorsal root ganglia via the pudendal nerve. Unlike the corpuscular-type endings in the penile shaft skin, most afferents in the glans terminate in free nerve endings. The efferent limb begins with parasympathetic preganglionic fibers from S2-S4 that pass in the pelvic nerves to the pelvic plexus. Sympathetic fibers emerging from the intermediolateral gray areas of T11-L2 Read more […]

Drugs That Stimulate Sexual Behavior

Various clinically used or experimental drugs enhance sexual interest or potency as a side effect in humans. Levodopa Levodopa (L-dopa) is a natural intermediate in the biosynthesis of catecholamines in the brain and peripheral adrenergic nerve terminals. In the biologic sequence of events it is converted to dopamine, which in turn serves as a substrate of the neurotransmitter norepinephrine. Levodopa is used successfully in the treatment of Parkinson’s syndrome, a disease characterized by dopamine deficiency. When levodopa is administered to an individual with this syndrome, the symptoms of Parkinson’s disease are ameliorated, presumably because the drug is converted to dopamine and thereby counteracts the deficiency. Individuals treated with levodopa, especially older men, have been observed to experience a sexual rejuvenation. This effect has led to the belief that levodopa stimulates sexual powers. Consequently, studies with younger men complaining of decreased erectile ability have shown that levodopa increases libido and the incidence of penile erections. Overall, however, these effects are short lived and do not reflect continued satisfactory sexual function and potency. Thus, levodopa is not a true aphrodisiac. Read more […]

Emerging Pharmacological Therapies For Erectile Dysfunction

In addition to Sheng Jing and acupuncture, which are old, and gene therapy, which is novel and new, other emerging therapeutics for erectile dysfunction are the following: • Phosphodiesterase inhibitors (sildenafil, viagra) • Cyclic AMP activators (vasoactive intestinal polypeptide) • Alpha-Adrenergic receptor antagonists (phentolamine, yohimbine) • Dopaminergic receptor agonists (apomorphine) • Alpha-Melonocyte stimulating hormone • Potassium channel modulators • Endothelin antagonists • Nitric oxide donors • Drugs topically applied to penis (transdermal or transglandular nitroglycerine, capsaicine, papaverine, or prostaglandin E1) • Viagra (Sildenafil) — In March 1998, the FDA announced that Viagra®, a new drug from Pfizer, Inc., has been approved as treatment for male sexual dysfunction • Cialis (Tadalafil) — Works fast — within 30 min in some patients — and can work up to 36 hours. • Vardenafil (Levitra) — Levitra is an FDA-approval oral prescription medication for the treatment of erectile dysfunction in men. The Herbal Virility herbs and minerals have been claimed to show specific improvements in the following areas: • Catuaba (bark) Read more […]