Anticancer Plants and their metabolites

The expanding global cancer burden necessitates an alternate therapy. Herbal therapy may be an effective alternative to chemotherapy. Researchers discovered that plants can fight cancer cells in the blood and breast. In vitro, plant secondary metabolites stimulated apoptosis-inducing enzymes and reduced cancer cell proliferation. More study is needed on plants, active compounds, and anticancer processes.

By: Aiman Saba, Maria Qamar, Ayesha Iftekhar, Nimrah Amen, M. Ajmal, Athar Mahmood, Maria Naqvi, Safura Bibi.

Plants have been used for centuries in traditional medicine and formerly a sector of all prescribed narcotics in industrialized countries comprise compounds derived from plants, directly or indirectly via semi-synthesis. Pakistan is enjoying an annoying and diverse flora of almost 5700 species of which about 2000 species are reported to be medicinally important. Though, the current species for Pakistan are far low than the trade of medicinal plants in other countries like India and China. Pakistan imported just spices of $33.29 million from India during 2008-2009. According to FAO Corporate Document Repository, the actual supply/demand of herbs and medicinal plants is in the range of 20,000 tons per annum. This diversity in Pakistan’s native flora reflects its wide-ranging climatic regions that ranges from arid and semi-arid to temperate and tropical. Some of the significant medicinal plants of Pakistan includes but not limited.

Anticancer plants species

Ephedra Procera used for the treatment of bronchial asthma, hay fever and heart intoxicant. Major supply of E. Procera to the world originated from Baluchistan Pakistan. Withania coagulans fresh fruit is vomitive, dried fruit is sedative, diuretic and gastric. Besides, it contains anti-cancerous compounds that have already been identified and also the local people drink its fruits extract for Hepatitis C. Hedera nepalensis the leaves and the berries are said to be cathartic, diaphoretic and stimulant. A decoction of the plant is used for the treatment of skin diseases. Aster thomsonii the Aster genus has been used for the relief of cough and it owns diuretic, antitumor, antibacterial, antiviral and anti-ulcer activities. Acer oblongifolium exhibits cytotoxic, antibacterial, anti-tumour and antifungal activities. Salvia nubicola plays significant role as antioxidant, cytotoxic, and anti-cancerous.  Euphorbia wallichii used for the treatment of edema, skin disorder, cutaneous anthrax and exanthema. Cytotoxicity (human cell line), antioxidant and DNA protection activities are also known. Rhazyastricta anti-cancerous and Allelopathic activities are known. Locally diabetic patients drink its leaves water extract.

Plants that become extinct now

It is matter of fact that these medicinal plants even in their usual habitat are facing number of challenges. Being weeds, they are in direct effect of ecological and climatic variations. Moreover, absence of uniform agriculture practices, pest infections, illegal collection practices and over-exploitation not only adversely effects the plant material for production of effective phytomedicines but also deplete the natural reservoirs of these important plants. It is notable that among, 5700 plant species of Pakistan, about 700 are endangered including 64 medicinal plants some of which are even extinct now e.g, Asparagus gharoensis, Ajuga bracteosa, Scaveolaplumererii, Scaveolataccada, Allium gilgiticum, Arabidopsis brevicaulis, Saxifragaduthei, Cousiniamatifeldei, Taraxacumchitralicum, Pediculariscaeruleoalbescens, Nepeta schinidii, Bruguieragymnorrhiza and Sonneratia caseolaris.

The use of modern-day biotechnological techniques through invitro cultures and micropropagation can be another solution where one can start production of medicinally significant ingredienst from lab scale to industrial scale production. This will not only produce opportunities for new research, but will also create opportunities for entrepreneurships.

Secondary metabolites of anticancer plants

The secondary metabolites in the plant kingdom such as polyphenols, flavonoids and brassinosteroids have been studied for their potential use as anticancer agents. Collectively they have been shown to possess anticancer activities which include; antioxidant activity; inhibition of cancer cell growth; induction of apoptosis; target specificity; cancer cell cytotoxicity. Compounds which have been identified and extracted from terrestrial plants for their anticancer properties include polyphenols, brassinosteroids and taxols.

Polyphenols

Polyphenolic compounds include flavonoids, tannins, curcumin, resveratrol and gallacatechins and are considered to be anticancer compounds. Gallacatechins are present in green tea. Polyphenols in a diet can improve health and reduce risk of cancers by being natural antioxidants. Cytotoxicity of polyphenols on a range of cancer cells has been demonstrated and their antioxidant properties determined. Cancer agents may be altered through the polyphenol regulating acetylation, methylation or phosphorylation by direct bonding. For example, curcumin treated cancer cells in various cells lines have exhibited inhibition of the Tumour Necrosis Factor (TNF) expression through interaction with various stimuli.

 Flavonoids

Flavonoids are from the polyphenolic compounds, constitute a large family of plant secondary metabolites with 10,000 known structures. They are physiologically active agents in plants and becoming of high interest scientifically for their health benefits. Various plants have been investigated for their flavonoid content and how these compounds affect cancer cells, such as fern species and plants used in traditional Chinese medicines like the litchi leaf. There is a high content of flavonoid compounds such as anthocyanins, flavones, flavonols, chalcones and many more which can be found in just one structure of the plant like its seed. Purified flavonoids have also shown anticancer activities against other human cancers including; hepatoma (Hep-G2), cervical carcinoma (Hela) and breast cancer (MCF-7).

Brassinosteroids

Brassinosteroids (BRs) are naturally occurring compounds present in plants which play roles in hormone signalling to control growth and differentiation of cells, elongation of stem and root cells and other roles such as resistance and tolerance against disease and stress. Also, BRs are used for regulation of plant senescence. They are essential for plant growth and development. BRs are another naturally occurring compounds which have demonstrated therapeutic significance is the cause against cancer.

Anticancer plant-derived drugs

Plant-derived drugs are desired for anticancer treatment as they are natural and readily available. They can be readily directed orally as part of patient’s dietary intake. Also, being naturally derived compounds from plants they are generally more tolerated and non-toxic to normal human cells. However, there are exceptions such as cyanogenetic glycosides, lectins, saponins, lignans, lectins and some taxanes. If plant-derived drugs can demonstrate selectivity in research, are non-toxic to normal cell lines and show cytotoxicity in cancer cell lines, these drugs can be led into clinical trials for further. The therapeutic development. Plant-derived drugs can fall under four classes of drugs with the following activities; methytransferase inhibitors, DNA damage preventive drugs or antioxidants, histone deacetylases (HDAC) inhibitors and mitotic disruptors.

Compounds including sulforaphane, isothiocyanates, isoflavones and pomiferin are considered to be HDAC inhibitors. They inhibit the activity of carcinogenic proteins. For example, sulforaphane has shown to inhibit important targets in breast cancer proliferation. Decreased expression of ER, EGFR and HER-2 resulted from HDAC inhibition by sulforaphane treatment in breast cancer cell lines.

Muaz Ameen

I'm Muaz Ameen, Master of philosophy in botany From University of agriculture Faisalabad. https://www.instagram.com/muaz.ameen

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