Researchers at Northeastern Ohio
Universities Colleges of Medicine and Pharmacy look at liver cancer and the
remedies, natural and synthetic, that can prevent and treat it. The abstract
sets up the need for this research:
Cancerous tumors
Despite significant advances in
medicine, liver cancer, predominantly hepatocellular carcinoma remains a major
cause of death in the United States as well as the rest of the world. As
limited treatment options are currently available to patients with liver
cancer, novel preventive control and effective therapeutic approaches are
considered to be reasonable and decisive measures to combat this disease.
Several naturally occurring dietary and non-dietary phytochemicals have shown
enormous potential in the prevention and treatment of several cancers,
especially those of the gastrointestinal tract.
The article then descrive the
largest group of phytochemicals used for medicine in India and China:
terpenoids, some of which are currently in clinical trials as anticancer
agents. Liver cancer is the fifth most common cancer and the third highest
cause of cancer-related deaths in the world, with a five year survival rate
below 9%. The incidence of liver cancer in the US has risen 70% in the last 25
years. The authors comment on treatment and prognosis:
HCC (hepatocellular carcinoma)
prognosis remains dismal despite many treatment options. Overall, the cure rate
among patients who undergo resection is not very high and for those patients
who are not eligible for surgery or percutaneous procedures, only
chemoembolization appears to improve survival…
Sorafenib, the only drug approved
by the United States Food and Drug Administration for the treatment of advanced
HCC, increases the median survival time by less than 3 month. However, this
drug does not defer the symptomatic progression of the disease, costs about $5400
per month for treatment, and exhibits severe adverse effects, including a significant
risk of bleeding. These drawbacks necessitate the search for novel preventive
and therapeutic approaches for this disease.
After a review of what terpenoids
are and how they are used, the article looks at plants and plant compounds with
anticancer effects. “Terpenoids have been found to be useful in the prevention
and therapy of several diseases, including cancer, and also to have
antimicrobial, antifungal, antiparasitic, antiviral, anti-allergenic,
antispasmodic, antihyperglycemic, antiinflammatory, and immunomodulatory
properties.”
In terms of anticancer properties
the article points out that a large number of triterpenoids suppress the growth
of many types of cancer cells “without exerting any toxicity in normal cells,”
and that preclinical studies show triterpenoids have chemopreventive and
therapeutic effects against colon, breast, prostate and skin cancer.
This is the first review we have
found that focuses exclusively on liver cancer. Of the compounds under current
study, these appear to be the most promising:
In vitro:
The only monoterpene studied was
geraniol, which inhibits the growth of liver cancer cells by inhibiting
HMG-CoA.
The diterpene andrographolide
from Andrographis paniculata (Burm.f.)
Nees inhibited growth by apoptosis
(inducing “programmed cell death” in the tumor cells) and two other mechanisms.
Two other diterpenes are discussed.
The largest number of compounds
studied are the triterpenes, with many active compounds, including those from
Black Cohosh (Actaea racemosa L.),
astragalus, Gotu Kola (Centella asiatica
(L.) Urb.), Trichosanthes kirilowii, Aesculus (horse chestnut), Reishi mushroom
(Ganoderma lucidum), Ginseng, Gynostemma, Bosewellia serrata, Aralia, Gentian
and others.
The tetraterpenes are known as
carotenoids and include the most common form of vitamin A (β-carotene) and
astaxanthin, the compound that makes shrimp and salmon pink. Fukoxanthin, from
seaweed, and lycopene from tomatoes also showed significant activity.
Sesquiterpenes with anticancer
activity in liver cells include bisabolol from chamomile and zerumbone from
wild ginger.
In vivo:
Animal studies for activity
against liver cancer are much less common, despite promising results from in
vitro studies. Of these, geraniol again showed the ability to suppress liver
carcinogenesis and limonene showed efficacy against HCC. Andrographis had
“potent antitumor activity” by oral administration. Bacoside A, from Bacopa
monniera delayed development and growth of tumors, and cucurbitacin B reduced
tumor volume and tumor growth. Escin (from horse chestnut) and ginseng reduced
tumor growth, as did glycyrrhizin from licorice.
Several studies Download here "Terpenoids as potential chemopreventive and therapeutic agents in liver cancer"
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