Modern Phytomedicine

Detoxification of Coir Dust

noreply@blogger.com (guhan) — Sun, 13 Sep 2009 16:22:00 +0000

The root elongation was affected by incubation time in a moist, limed and limed with addition of FeSO4 . At moisture of 50% (v/v) the phytotoxicity of both coir dust and coconut shell decreased with incubation time. After 10 weeks incubation at 20C, the percentages of root length in media to control increased from 17.7 to 65.1% for fresh fine coir dust (0.5–1 mm), from 29.8 to 62.6% for fresh coarse coir dust (1–2 mm) and from 61.1% to 86.6% for fresh coconut shell (2–4 mm). A similar result was found in a mixture of fresh coir dust samples.

However, the incubation for up to 10 weeks at moist condition was insufficient to detoxify both coir dust samples . The change with incubation time for moist coconut shell lasted up to 5 weeks . Liming had been shown to further reduce the phytotoxicity of fresh coir dusts and coconut shell . The liming increased the process of detoxification of fresh coir dusts and coconut shell. Limed fresh coir dust (1–2 mm), a mixture of coir dust samples and fresh coconut shell (2–4 mm) had been fully detoxified by incubation at 20C for 3 weeks. For the limed fresh fine coir dust (0.5–1 mm), a minimum of 6 weeks was needed .

Compared with liming, addition of FeSO4 tended to decrease the phytotoxicity of coir dust and coconut shell, but it was not significant for fresh fine coir dust (0.5–1 mm) and for a mixture of coir dusts. The process of detoxification was affected by incubation temperature. For a moist mixture of seven coir dust samples, high incubation temperature could decrease its phytotoxicity, while for the mixtures with addition of lime or plus FeSO4, high incubation temperature was found to be effective only in the initial 2 weeks . In a potential potting mix of 50% aged coir dust and 50% coconut shell (0.5–2 mm), incubation at high temperature was found to reduce phytotoxicity more effectively than at low temperature .

Incubation for 6 weeks at was sufficient to fully detoxify the amended potting mix .Because the fine coconut shell (<0.5 mm) contained 33 mg L1 phenolic compounds , the root elongation in the mix containing the fine coconut shell was severely inhibited. With incubation at 20C the percentage of root length in the mix to control was increased onlyfrom 19.6 to 37.2% .

P & D -- MATERIALS AND METHODS

noreply@blogger.com (guhan) — Sat, 29 Aug 2009 16:37:00 +0000

Fresh coir dust, coconut shell and aged coir dust were obtained from

the Philippines. Some chemical properties of the samples were determined
using the Australia Standard methods To evaluate the phytotoxicity of coir
dust and coconut shell, a rapidbioassay method was used with lettuce
because the plant is a most sensitive species.

The moist sample of 50mL was weighed and placed in a petri dish to depth
about 9mm for the bioassay. The moisture of the sample was estimated
by its weight and bulk density. According to its moisture, water was
added to the petri dish to the water holding capacity of the sample. Ten
lettuce seeds were sown on the surface of the media in the petri dish. The
petri dish was covered with lid and incubated at room temperature
for 7 days. Finally, the root length was measured since the
roots were more sensitive to phytotoxins than shoots of lettuce. A known
nontoxic medium consisting of 0.5 L moist peat moss, 0.5 L sand, 4 g L1
dolomite, 0.75 gL1 KNO3, 1.0 gL1 single superphosphate, and

Sample pH (1:1.5) EC Cl

Fresh fine coir dust (0.25–1 mm) 6.11 0.80 450
Fresh coarse coir dust (1–2 mm) 5.89 0.60 300
Fresh coir dust (mixture) 5.90 0.68 364
Aged coir dust (unscreened) 5.89 0.51 300
Fresh coarse coconut shell (2–4 mm) 6.47 0.71 100
Fresh fine coconut shell (<2mm) 6.05 1.74 425

0.6 gL1 mixture of micronutrients as a bioassay control. There were two
replications in the bioassay procedure. The phytotoxicity was expressed
as the percentage of root length in the sample to the control. There was
no fungal growth in petri dishes.To investigate the effects of incubation time,
temperature and amendments on the phytotoxicity of fresh coir dust and
shell, the samples of fresh coir and coconut were treated by

(i) moistening with 500mLL1 water (moist),
(ii) liming with 5 gL1 calcium carbonate(limed) and with 500mLL1 water, and
(iii) plus 0.5 g L1 ferrous sulphate (limedþFe).

The treated samples were kept in plastic bags and incubated in an incubator
the dark and at different constant temperature systems. The samples were
taken for bioassay every week for several weeks. After incubation, pH and EC of
the incubated samples were determined in the suspension of sample and
distilled water at the ratio of 1:1.5 .

Phytotoxicity and Detoxification(P & D)

noreply@blogger.com (guhan) — Sat, 29 Aug 2009 16:30:00 +0000

Coir dust is the remaining waste product when long fibers are
extracted from coconut husk. It constitutes the short fibers and mesocarp pith of coconuts. Because coir dust has many characteristics, such as high water-holding capacity and slow decomposition, it has been extensively used as an environmentally friendly substitute for natural peat in potting media. In addition, coir dust has been used as a soil amendment.

Because unripe nuts are usually soaked in brine to make the fiber easier to extract, the problem of excess salinity with some coir dust products has been recognized. The physical and chemical properties of coir dusts varied significantly with source, degree of grinding, screen size, and age. With increasing needs in production of coir-based media and as a soil amendment, the use of coir dust is currently shifting from the aged coir dusts, e.g., 100 year old Sri Lankan coir, to young, even fresh, coir dusts.

The use of fresh coir dusts can involve serious problems of high salinity , and phytotoxicity. In a comparative study of peat and other media for containerized forest tree seedlings, it was found that no plant of E.urophylla survived and growth of E. deglupta wasseverely retarded in coir dust media. Unfortunately, the salinity and phytotoxicity of the coir dust were not determined. One possibility for the phytotoxicity could be the phenolic compounds in the coir dust, like uncomposted sawdust and bark if the Cl content in the coir dust was normal.

The phytotoxicity of the potting substrates based on barks and
sawdusts has been extensively studied and varies with species and age of source trees. Most of the barks and sawdusts used in potting media contain phytotoxins which were found to be phenolic compounds. It was found that catechin, procyanidins B-1 and B-3, and 3,5,30,40-tetrahydroxystilbene and its glucoside from Pinus radiata bark and ellagitannins from sawdust of E. regnans and E. camaldulensis were responsible for the phytotoxicity. Addition of a phenol-fixing compound to aqueous substrate extracts markedly reduced the phytotoxicity.

noreply@blogger.com (guhan) — Tue, 19 Aug 2008 13:42:00 +0000

Modern Phytomedicine: Turning Medicinal Plants intoDrugs.

Medicinal preparations derived from natural sources, especially from plants, have been in widespread use since time immemorial. Ancient texts of India and China contain exhaustive depictions of the use of a variety of plant-derived medications.In fact, plants remain the main source of medicines for a large proportion of the world’s population, particularly in the developing world, despite the advent of the pharmaceutical chemistry during the early twentieth century, which brought with it the ability to synthesize an enormous variety of medicinal drug molecules and al-lowed the treatment of previously incurable and/or life threatening diseases.Not surprisingly, chemically synthesized drug gained popularity and became the basis of pharmaceutical industry. Over the years, however, synthetic drugs have been plagued by unwanted side-effects, toxicity, and inefficiency, among other problems. In addition, the search for new drugs against a variety of illnesses through chemical synthesis and other modern approaches has not been encouraging. These factors, as well as the emergence of new infectious diseases, the proliferation of disorders such as cancer, and growing multidrug resistance in pathogenic microorganisms, have prompted renewed interest in the discovery of potential drug molecules from medicinal plants.
Herbal medicine is now globally accepted as a valid alternative system of therapy in the form of pharmaceuticals, functional foods, etc., a trend recognized and advocated by the World Health Organization (WHO). Various studies around the world, especially in Europe, have been initiated to develop scientific evidence- based rational herbal therapies. Though ancient medical treatises have documented a large number of medicinal plants, most have remained undocumented and uncharacterized, the knowledge of their use being passed down from generation to generation by word of mouth. New plant sources of medicine are also being discovered.
Here we have made an attempt to bring together recent work and current trends in the field of modern phytomedicine from different parts of the world. Although there are a number of blogs available on medicinal plants and phytocompounds, this blog has unique contributions in the form of chapters from experts in the field starting from the concept of phytoscience, screening biological activities against problematic infectious agents such as multidrugresistant bacteria, fungi, and viruses. Discussion of types of herbal remedies, problems associated with herbal medicines, such as efficacy, adulteration, safety, toxicity, regulations, and drug delivery etc. are included as contributions by different learned experts.
Today’s use of medicinal plants and bioactive phytocompounds worldwide and our scientific knowledge of them comprises the modern field of the “phytosciences.” The phytosciences have been created from the integration of disciplines that have never been linked before, combining diverse areas of economic, social, and political fields, chemistry, biochemistry, physiology, microbiology, medicine, and agriculture. The field is unique among the biomedical sciences in that instead of testing a hypothesis, in the phytosciences researchers try to determine whether plants commonly used in traditional medicine brings benefits for health and, if so, what their mechanisms of action are.
Despite the common belief that phytocompounds are safe, they all have inherent risks just like synthetic compounds. Thus it is within the scope of the phytosciences to elucidate side-effects, appropriate doses, identify bioactive phytocompounds and ways of extraction and conservation. Besides these, legal aspects regarding regulation of the prescription and commercial sale of medicinal plants are a matter of debate all around the world. The varied regulations in different jurisdictions regarding the prescription and sale of these products add confusion to the formal use of phytocompounds.
As a multidisciplinary science, research in the phytosciences is almost unlimited, which makes it impossible to discuss all aspects of this emerging science in just one page. Therefore, we have focussed here mainly on the antimicrobial activity of bioactive phytocompounds, discussing their use against multidrugresistant (MDR) bacteria and fungi, their mechanisms of action, and their interactions with macromolecules and potential for toxicity in mammalian cells. Technical aspects regarding the development of fast and reliable methods of extraction, high output screening systems, and bioautography of essential oils and crude extracts and fractions have also been discussed. Problems related to the efficacy, stability,drug delivery systems and quality control are also commented on.Overall this chapter aims to provide a better understanding of the modern field of the phytosciences and its application in the world today.