Category Archives: Scientific delights

Flavonoid Content In Certain Tropical Plants

Lovely piece of data: Miean KH, Mohamed S. Flavonoid (myricetin, quercetin, kaempferol, luteolin, and apigenin) content of edible tropical plants. J Agric Food Chem. 2001 Jun;49(6):3106-12. PubMed PMID: 11410016.

Total flavonoids:

  • onion leaves (1497.5 mg/kg quercetin, 391.0 mg/kg luteolin, and 832.0 mg/kg kaempferol)
  • Semambu leaves (2041.0 mg/kg)
  • bird chili (1663.0 mg/kg)
  • black tea (1491.0 mg/kg)
  • papaya shoots (1264.0 mg/kg)
  • guava (1128.5 mg/kg).

The major flavonoid in these plant extracts is quercetin, followed by myricetin and kaempferol.

Luteolin could be detected only in:

  • broccoli (74.5 mg/kg dry weight)
  • green chili (33.0 mg/kg)
  • bird chili (1035.0 mg/kg)
  • onion leaves (391.0 mg/kg)
  • belimbi fruit (202.0 mg/kg)
  • belimbi leaves (464.5 mg/kg)
  • French bean (11.0 mg/kg)
  • carrot (37.5 mg/kg)
  • white radish (9.0 mg/kg)
  • local celery (80.5 mg/kg)
  • limau purut leaves (30.5 mg/kg)
  • dried asam gelugur (107.5 mg/kg).

Apigenin was found only in:

  • Chinese cabbage (187.0 mg/kg)
  • bell pepper (272.0 mg/kg)
  • garlic (217.0 mg/kg)
  • belimbi fruit (458.0 mg/kg)
  • French peas (176.0 mg/kg)
  • snake gourd (42.4 mg/kg)
  • guava (579.0 mg/kg)
  • wolfberry leaves (547.0 mg/kg)
  • local celery (338.5 mg/kg)
  • daun turi (39.5 mg/kg)
  • kadok (34.5 mg/kg).

In vegetables, quercetin glycosides predominate, but glycosides of kaempferol, luteolin, and apigenin are also present. Fruits contain almost exclusively quercetin glycosides, whereas kaempferol and myricetin glycosides are found only in trace quantities.

On The Application Of The Principle Of Scale In Molecular Biology

When one considers receptor interactions with substrate and the chemical environment of a cell in general, one should keep in mind that a macroscopic view of these processes may not fully describe what is actually going on on a cell’s surface.

For example, let’s consider the rain. The process of rain from a meteorological perspective is explained by the condensation of water vapors in the upper or lower layers of the atmosphere, with the force of gravity subsequently acting on the vapors, condensed intro drops, making them fall down to earth. However, this view describes little of the experience of the rain for those who are  witnessing it on the ground, for whom the multitude of drops appears, as a poet put it, as “dewy locks.”

The process of a cell’s interaction with its chemical environment can be seen through this analogy. More than just chemicals – it’s also a physical process, since, at this scale, a molecule is perceived as an electromagnetic field, and the process of interaction between the substrate and its receptor being perhaps akin to the experience of the rain for a typical human observer, since the presence of the substrate may be perceived by the receptor as a multitude of electric impulses.

This is, essentially, an example of “self-identification” as a method of cognition, expounded upon in certain esoteric and metaphysical teachings teaching, such as some of the yogic tradition. In this regard, here the cell may be perceived as a “planet,” while the receptor is some kind of an entity, such as a human; and the interactions of the latter with the substrate are experienced as “rain.” That is, we perceive the existence of the two “worlds,” surrounding the primary object of cognition, as the ones immediately “above” and “below” it.

While this is hardly science, this method may help one to understand the relationship of the receptor to the cell and its surrounding environment.

Serum Metabolites Of Plant Extracts Decrease Hepatic Lipid Synthesis

A recently published research paper provides an example of use of an original experimental model. In this study, human hepatic cells were treated with serum metabolites of proanthocyanidin-rich extracts of cocoa, French maritime pine bark, and grape seed administered to rats. All groups of metabolites reduced lipid synthesis by the cells, including that of free cholesterol, cholesterol ester, and triglycerides. In particular, the grape seed extract metabolites reduced the lipid synthesis more so than the extract administered to the cells directly (Abstract).

This study is interesting for the reason that it appears to use an original research model, using metabolites of plant extract to be administered to cells in vitro. The preponderance of in vitro research to date appears to largely ignore the metabolic fate of plant compounds administered to both humans and animals. The compounds or preparations are applied to the cells directly and the effect is observed. This, however, may generate data that is incompatible with real-life circumstances, since ingested compounds rarely enter the blood – and, hence, all the internal tissues – unmetabolized. It may be painful to acknowledge that, because of this, the usefulness of most of the in vitro data to date is limited. In this study, the scientists found an original, if not to say, smart, way to circumvent this problem without having to perform costly pharmacokinetic experiments and synthesis of new molecules. We congratulate them on their ingenuity.

Turmeric: Not Just Curcumin!

Curcumin

Most people with even a basic knowledge of herbal medicine will tell you that the activity of an herb can not (or should not) be reduced to the activity of just one substance. However, the research on curcumin – considered the “primary bioactive component” of the famous spice turmeric – is so seductive that many people in the natural health crowd have started associating turmeric root mainly with that one particular compound.

[Note: The highlighted numbers below link to abstracts in PubMed.]

However, as one group of researchers pointed out, curcumin-free turmeric still possesses remarkable bioactivity (23847105). According to them, this bioactivity can further be traced to other chemical compounds in turmeric, such as turmerin, turmerone, elemene, furanodiene, curdione, bisacurone, cyclocurcumin, calebin A, and germacrone. In another study, a total of 19 antitumor constituents of turmeric were identified (24079186). Other researchers also mentioned β-elemene, δ-elemene, furanodienone, and curcumol (22820242). Many of these are constituents of turmeric’s volatile oil, i.e., they are associated with the aroma of turmeric, and their content is severely reduced in dry turmeric, which is the most familiar form of this herb to most people. Nevertheless, some studies are available on these individual compounds, which may enlighten us to the action of the whole herb, rather than just the highly concentrated fraction of curcuminoids.

[Update: A new study reports that curcuminoid- and oil-free turmeric extract possesses significant antiinflammatory activity (24454348).] Continue reading

The Alchemy Of Curcumin

Turmeric, the golden spice

Photo by Badagnani

Curcumin’s differential effects on healthy vs. cancer cells may be due to its interaction with metals

One of the most intriguing findings of the modern scientific research of herbal medicine is the finding that plants’ actions may vary depending on the condition of the organism. For example, Echinacea will stimulate the immune system in the condition of the disease, but tone down the pro-inflammatory effect (hence the term “immunomodulators”). Compounds from American ginseng (Panax quinquefolius) will kill cancer cells but “not touch” normal cells. Similarly, curcumin is known for its differential activity towards healthy vs. cancer cells.

The “magical” interaction of curcumin with metals

This fascinating article points to the theory that such differential action might be due to the interactions between the plant substances and metals. Apparently, it is a well-known fact that many disease sites (especially those of cancer and Alzheimer’s disease) are associated with increased concentrations of certain metals – called transition metals, such as copper, zinc, and iron. This is the property that curcumin seems to interact with: In the normal cellular environment, it acts as an antioxidant; while surrounded by high levels of metals in a different-than-normal oxidation state, it turns into a rabid reactive oxygen species producer.

The ancients may have been on to something!

This leads to some interesting conlusions: First of all, the rishi, to whom the origins of Ayurvedic medicine are usually ascribed, may have been onto something with their use of metals in Ayurvedic formulas. Could they have discovered – empricially or otherwise – that metals interact with herbs’ activities in some way?

And also, this makes me amazed once again at the time we are living in: that of the crossroads of traditional knowledge and modern science.