What s going on with the absorbance of plant anthocyanins

Anthocyanidin, also known as anthocyanidin, is a class of water-soluble natural pigments widely found in plants in nature. It is also the main coloring substance in plant petals, and most of the colorful colors such as fruits, vegetables, and flowers are related to it. Under the different pH values of plant cell vacuoles, the petals show colorful colors.

In autumn, the soluble sugar increases, the cells are acidic, and they are red under acidic conditions, so the red leaves are anthocyanins, and the depth of their color is positively correlated with the content of anthocyanins, which can be quickly determined by spectrophotometer, and is blue under alkaline conditions. The color of anthocyanins is affected by many factors, and adverse environments such as low temperature, hypoxia, and phosphorus deficiency can also promote the formation and accumulation of anthocyanins.

Anthocyanins give flowers and fruits their bright colour and attract animals to help pollinate plants and disperse seeds.

The main hypotheses of anthocyanins in young leaves include: (1) fungicidal effect, (2) photo-protection, (3) antioxidant, and (4) anti-herbivore

Anthocyanins are colored, and their absorption of light of the same color is the weakest, and the better the permeability of the cell membrane, the better the light absorption!

Plants are strong against environmental stresses by producing a wide variety of secondary metabolites. Anthocyanins are one of the phenylpropanoids widely found in higher plants, which make the flowers, fruits, stems, leaves and other organs of plants appear red, purple and blue.

Anthocyanins not only help plants resist adversity stresses such as ultraviolet radiation, strong light, low temperature, and nutrient deficiency, but also play an important role in the interaction between plants and insects. Therefore, the accumulation of anthocyanins is considered to be a visual molecular marker that can be used to determine whether plants are experiencing adverse environments during growth.

Anthocyanidin, also known as anthocyanin, is a kind of water-soluble natural pigment widely found in plants in nature, belonging to flavonoids, and is also the main color substance in plant petals, most of the colorful colors such as fruits, vegetables, and flowers are related to it, and are widely present in flowering plants (angiosperms) of 72 genera in 27 families. Anthocyanins mainly accumulate in plant vacuoles and have a variety of physiological functions, and are the most powerful free radical scavengers discovered so far, with antioxidant aging, anti-mutation, anti-cancer and anti-arteriosclerosis functions. In addition, anthocyanins are a safe, non-toxic natural food coloring. Therefore, anthocyanins have certain application potential and research value in horticulture, medicine, cosmetics, food, etc.

Plants with high anthocyanin content include grapes, mountain plants, pine needles, purple potatoes, ginkgo biloba, peanuts, apples, tea, sea buckthorn, etc., and the most studied grapes and purple potatoes are currently the most studied.

In its natural state, anthocyanins are often combined with various monosaccharides in plants to form glycosides, called anthocyanins, which were proposed by Marguart (1853) when he named the blue extract from cornflower flowers, and are now used as a general term for similar substances.

Anthocyanin biosynthesis is mainly determined by plant genotype, but the role of environmental and human factors cannot be ignored. Light activates light.

Sensitin promotes the synthesis of photoregulatory enzymes and increases their activity, and also uses cryptochrome as a receptor to affect the synthesis of anthocyanins during cell stabilization.

Influencing factors on anthocyanin formation: the type of carbon source affects the production of anthocyanins in plant cells, the effect of hormones on anthocyanin production in plant cell culture, the effect of temperature on anthocyanin production in plant cell culture, the effect of nitrogen source on anthocyanin production in plant cell culture, the effect of precursor additives on anthocyanin production in plant cell culture, and the effect of light on anthocyanin production in plant cell culture.

Anthocyanins can be produced when the temperature difference is large enough to a certain value.

1: Determination method of proanthocyanidins (spectrophotometry).

This method is suitable for the determination of proanthocyanin content in various plant tissues, organs and their preparations, such as grape seed and pine bark extracts.

1.How-to summary.

Proanthocyanidins (also known as condensed tannins) are oligomers and multimers of flavan-3-ol, which are polyphenolic compounds. Unlike other phenolic compounds, flavanols (condensed tannins, monomers, dimers, etc.) can react with vanillin in acidic media to produce a colored substance with maximum absorption at 500 nm, the content of which can be measured by colorimetry.

2.Instrument.

Spectrophotometer.

3.Reagent.

The water used is deionized water or distilled water of equivalent purity.

1) Vanillin, methanol, and concentrated hydrochloric acid are all analytically pure grades.

2) Purified proanthocyanidins or catechins.

3) 4% vanillin methanol solution.

4) Standard solution: dissolve the purified proanthocyanidins in distilled water to make a 1mg ml stock solution, and dilute the stock solution to a concentration of 1 10-2mg ml to 1mg ml standard solution. The standard solution should be prepared on the day of the measurement.

If there is no purified proanthocyanidin, catechins can be used instead, and the preparation method is the same as above.

4.Assay steps.

1) Preparation of proanthocyanidins in samples: plant materials are extracted by 4 times the volume of acetone + water (7 + 3, volume ratio) or 60% methanol, distilled under reduced pressure below 40 to remove organic solvents, and the aqueous phase is washed by ether and then fixed volume.

Freeze-dried solid proanthocyanidins are directly dissolved in water (with a small amount of methanol to help dissolve) to make proanthocyanidins solution.

The original anthocyanidin solution should be stored in a dark environment for 5 years for later use.

2) Sample determination: Wrap the test tube (14mm 20mm) tightly with tin foil, and only leave the nozzle for sample filling. The sample was added to the tube, and then 4% vanillin methanol solution was added, and then concentrated hydrochloric acid was added, mixed thoroughly, and the color was developed at room temperature for 15min.

This can also be done in a dark environment. Finally, colorimetric at 500 nm.

A standard curve can be prepared according to the above steps (i.e., the absorption value of the proanthocytidins at 500 nm is.

5.Result calculation.

The formula for calculating the amount of proanthocyanidins is that proanthocyanidins (1 10-3 mg) = a500 nm

where v – sample dilution volume (folds).

6.Exegesis.

1) The detection range of this method is (5 500) 10-3mg sample solution. Precision and accuracy greater than 1 10-3 mg.

2) The reaction test tube should be soaked in detergent for 24h and washed thoroughly.

3) When colorimetry, use water as a blank.

4) The OD value at 500nm should be controlled below 3.

5) When the original anthocyanin content of the sample is high, the value measured without vanillin should be subtracted from the A500nm value measured in the presence of vanillin.

6) The chromogenic solution should be kept away from light.

In addition, there is a pH differential method.

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Methods for the determination of anthocyanin content:

Principle: Anthocyanins are one of the widely distributed pigments in plants, belonging to flavonoids, flavonoids play a regulatory role in plant growth, and have been valued by people. Anthocyanins show different colors under different pH conditions, and are red in acidity, and their color shades are proportional to the anthocyanin content, which can be determined by colorimetric method, and the method is simple and easy.

Instrument Drug: Model 721 Classified Photometer Incubator.

Table balance scissors.

Beaker Graduated cylinder.

mol/l hcl

Operation steps: Weigh 1g of the material, cut it into 2 3mm pieces, put it in a beaker, add 10ml of HCl (increase or decrease the amount of HCl according to the anthocyanin content), and cover the cup with weighing paper to prevent evaporation. Place in a 32-temperature chamber and immerse for at least 4 hours. Then filtered, the filtrate was taken and the absorbance was read with a spectrophotometer at a wavelength of 530nm, and mol l HCl was used as the blank control, and a cuvette with an optical diameter of 1cm was used.

The concentration of anthocyanins when absorbance A530 is called 1 unit to compare the relative amounts of anthocyanins. Multiply the measured absorbance by 10 to represent the relative concentration unit of anthocyanins.

1 1 2 Instruments and Reagents.

The 760CRT dual-beam ultraviolet-visible spectrophotometer is used.

The reagent is 2 methanol hydrochloride solution: concentrated hydrochloric acid: 99 methanol (2:98).

1 2 Methods.

1 2 1 Sample Processing.

Cut the veins of fresh leaves of trees containing anthocyanins into 1 2 mm pieces, randomly sample, accurately weigh 0 2 g, and place in a 50 ml beaker.

Add 10 ml of 2 methanol hydrochloride solution to soak, tie the mouth of the cup tightly with parafilm to prevent volatilization, and place it at room temperature in a dark place for 2 hours until the naked eye.

Observe that the leaf tissue completely turns white, take it out and filter, and use 2 hydrochloric acid methanol solution to set the volume into a 50 ml volumetric flask, and put it on a UV-visible spectrophotometer.

Analyse. 1 2 2 Assay.

Full wavelength scanning on a UV-Vis spectrophotometer 2 Absorption spectra of the extraction solution of the leaves extracted in methanol hydrochloride, results table.

The maximum absorption wavelength in the ultraviolet region is around 280 bricks, and the maximum absorption wavelength in the visible region is within 500 550 bricks [citation]. its maximum absorption wave.

It was measured at 530 535 i] n and was quantitatively determined at a wavelength of 530 nm. Use 2 methanol hydrochloride solution as a blank control on a UV-Vis spectrophotometer with a 1 EM thick cuvette at a wavelength of 530 nln

The absorbance is determined at (a).

The anthocyanins of plants are mainly controlled by genetic factors, such as purple sweet potato and purple cabbage.

Du purple, but the depth is different. However, the anthocyanin content of a plant will be affected by external factors such as light, temperature, humidity and other external factors in the growth environment, and the anthocyanin content of plants will increase due to shorter light hours and lower temperature, as well as drought will increase the anthocyanin content of plants, such as the stems and leaves of spinach in winter will turn purple, and the leaves of maple trees will turn from green to purple and then to red, etc., and excessive drought will also increase the anthocyanin content of plants. Therefore, under the premise of selecting the required plant varieties, the production of anthocyanins can be affected by controlling and adjusting the light and temperature.

It is important to note here that the pH only affects the appearance of anthocyanins, i.e., the different colors they exhibit, not the amount of their content.

No, anthocyanins are found in the vacuoles of plants, whereas the organelles that carry out photosynthesis in plants are chloroplasts. Expert.

The only aspect of photosynthesis is visible light, because chlorophyll, the pigment that plays a role in photosynthesis, absorbs visible light. There are two types of chlorophyll in chloroplasts: chlorophyll a and chlorophyll b.

Only chlorophyll a is directly involved in photosynthesis, and the light absorbed by chlorophyll b can only be used in photosynthesis after being transmitted to chlorophyll a, so chlorophyll b is called an auxiliary pigment. In addition to chlorophyll, chloroplasts also have other orange-yellow pigments called carotenoids. The light absorbed by carotenoids can also be passed on to chlorophyll a, so they are also auxiliary pigments.

Although carotenoids do not directly participate in photosynthesis, they have a protective function of absorbing and consuming excess light energy in bright light, otherwise light may destroy chlorophyll.

Anthocyanins are mainly used for stress resistance, and they mainly make the leaves appear color.

The effect of color development, anthocyanins are generally in vacuoles.

Different plants have different characteristics (including shape and shape) in their flowers, and anthocyanins are one of the main pigments that make up the color of petals and fruits. So anthocyanidin, also known as anthocyanins. There are more than 300 different anthocyanins in nature.

Different species of plants are naturally bred in the process of their own evolution, and retain their colors that are conducive to their own reproduction. Of course, artificial breeding can also cultivate the flower color that people like.

Well. Anthocyanins are potent UV blockers and melanin inhibitors.

The main effect of anthocyanins is antioxidant, and it does not play a protective role in ultraviolet radiation, but anthocyanins can effectively **** the damage caused by long-term sun exposure. Freeze-dried anthocyanins are fermented and freeze-dried from blueberries, blackberries, black goji berries, blackcurrants, red goji berries, cranberries, mulberries, blue indigo berries, and red raspberries. Maintain the activity of beneficial bacteria and anthocyanins in the berries, Under vacuum conditions, when the water vapor is directly sublimated, the berries and active substances remain in the ice shelf when frozen, forming a sponge-like loose porous structure, so its volume and size are almost unchanged after drying.

It is rich in proanthocyanidins OPC, proanthocyanidins, and superoxide dismutase (SOD).

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