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The Star Online: Lifestyle: Health

A new approach

Posted: 20 May 2014 09:00 AM PDT

ASIA has a long history of traditional herbalism – think Ayurvedic, Chinese, Tibetan and Unani medicine.

The 1960s heralded a global shift towards synthetic medication, partly fuelled by advances in mapping the human genome and our understanding of molecular biology.

There was also the notion that synthetic drugs with specific targets were safer, with less room for side effects.

Recently, however, plants have come back in vogue as a medicinal source. As our knowledge and understanding of disease has grown, so too has the number of possible new drug targets.

Instead of relying on the finite number of chemical compounds that we do know, or being restricted by the various limits of synthesising new drug structures, mining the millions of undiscovered, unique plant compounds is beginning to look like an attractive option.

Furthermore, as we've mentioned earlier, Malaysia is among the world's richest places in terms of biodiversity.

Despite this, next to no blockbuster drugs have emerged from the country – ever.

Of the ones that do show promise – the anti-HIV compound Calanolide A, for example, or the potential anti-cancer agent, Silvestrol, both of which come from trees that grow in Sarawak – a lot of the work was either instigated or funded by foreign institutions, with some local input.

Even then, it's been over two decades since the initial hype over Calanolide A, and 10 years since Silvestrol was discovered; both are still undergoing clinical trials.

The length of time and money to get a drug to market is one investment few Malaysian companies are prepared to make.

And with no private sector players willing to partner and invest in commercialising the work of research institutions, there is no product.

This is the general landscape of drug development in Malaysia.

To date, no Malaysian herbs have led to high-claim drugs emerging on the market. The only products you will find are herbal teas or supplements for general health and ailments.

USM-based Amin Shah Malik Abdul Majid, who is developing an anti-angiogenic herbal drug from misai kuching, knew he had his work cut out for him; but he was hopeful that a different approach to drug development would make a difference.

Instead of developing a single-target drug based on one active compound, his product would be a standardised herbal extract, containing a mixture of naturally occurring active compounds.

Multi-target drugs are an emerging trend, and herbal extracts are thought to hold promise in complicated multi-factor diseases like cancer.

Importantly, they also generally cost a lot less to develop.

Amin explains: "Let's say you have found an active compound in a plant extract and you want to manufacture a drug from it.

"To do that, you have to isolate that compound from the plant extract. That will involve an expensive purification process.

"The alternative is to synthesise an analogue of that compound, which is also very expensive," he says.

Whereas in herbal extracts, you boil the plant, use a solvent to extract the active compounds, and then prove that their biological activity meets quality control standards.

To qualify as a herbal drug, however, the concentration of active compounds within an extract needs to be standardised. Each dosage must be safe and have a consistent affect.

"Herbal extracts can be very complicated," he adds. "Take a mango, for instance. Every harvest may yield fruits with a slightly different level of sweetness. It's the same with variations in the concentration levels for different compounds within a plant extract – this could result in different levels of potency for the active compound.

"Too little, and there may not be an effect; too much, and it may be toxic."

Herbal extracts have been used in traditional medicine for centuries, albeit without the science to back them up.

Until recently, however, they were never deemed practical for use in the pharmacological world. Now, Amin says, technology has made otherwise tedious analytical processes less labour-intensive – making herbal extracts a more financially feasible area of exploration.

Kredit: www.thestar.com.my

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