Quality evaluation and preliminary antioxidant activity study of Dahua Huangmudan seeds
Paeonia ludlowii is one of the eight species of Paeonia sect. Moutan DC. of the Paeoniaceae family in China. It is endemic to Xizang and belongs to a cluster of deciduous shrubs. It is only found in Nyingchi in southeast Xizang. The Dahua Yellow Peony has large and colorful flowers, making it an extremely precious ornamental peony variety. Its roots and petals can be used as medicine, and it has certain edible and medicinal value. Although the large yellow peony has high breeding and ornamental value, due to its narrow distribution and continuous population decline, it has been listed as an endangered plant in the “Red List of Chinese Species” and is in a critically endangered state. The research on the chemical composition of peonies mainly focuses on the roots, with little research on other parts. Since 1753, over 180 compounds have been isolated. Its chemical composition mainly includes monoterpenes, monoterpenoid glycosides, triterpenoids, phenols, tannic acids, flavonoids, etc. Palmitic acid is a raw material used in the production of candles, soap, lubricants, softeners, and synthetic detergents. Oleic acid has unique antioxidant properties and is currently the safest healthy fatty acid. Oleic acid can regulate blood lipid levels, lower cholesterol, and prevent memory decline; At the same time, it has good therapeutic effects on metabolic disorders, skin damage, etc. Linoleic acid can soften cardiovascular and cerebrovascular systems, lower blood pressure and blood lipids, accelerate human metabolism, effectively prevent arteriosclerosis, enhance immunity, promote bone development, improve memory, and also delay aging. Linoleic acid is one of the essential fatty acids in the human body, which can degrade blood clots, prevent cardiovascular and cerebrovascular diseases, inhibit the occurrence and metastasis of cancer, suppress allergic reactions and anti-inflammatory effects, inhibit aging, enhance intelligence, and protect vision.
In recent years, research on the large flowered yellow peony has mainly focused on plant classification, habitat communities, and cultivation and reproduction; There are relatively few reports on the chemical composition and activity evaluation, and only Zeng et al. used GC-MS to analyze the content of palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid in the seeds of Paeonia lactiflora. Zhang et al. identified 20 types of fatty acids in the oil of peony seeds, while there have been no reports on the quantitative analysis of palmitic acid, oleic acid, linoleic acid, and linolenic acid in peony seeds using QAMS. This study combines one test and multiple evaluations with fingerprint analysis to establish a quality evaluation method for the seeds of Dahua yellow peony. The antioxidant activity of Dahua yellow peony and oil peony seeds was compared and evaluated by DPPH method and Fe3+reduction method. The experimental results will contribute to the development of new products for the seed oil and seed coat of Dahuahuang peony, providing scientific basis for the comprehensive development and utilization of Dahuahuang peony, and also providing useful ideas for the quality evaluation of different varieties of peony seeds.

 

According to the field survey and literature review by the research team, the Dahuang Peony is only distributed in Linzhi City, Xizang. From the fingerprint spectrum results, it can be seen that the similarity of the 10 batches of Dahua Yellow Peony samples is higher than 0.99, indicating that the Dahua Yellow Peony produced in the Nyingchi area has a high similarity. The similarity results indicate that the distribution of Dahua Huangmudan is concentrated and the variation is small; Through PCA analysis, it can be seen that the Dahua Yellow Peony is clearly distinguished from peony samples from several other production areas. The calculation results of QAMS method are basically consistent with those of external standard method, indicating that QAMS method can be used for quantitative analysis of multiple components in peony seeds, and also provides a new and reliable method for quality control of other peony seeds in China. From the content results, it can be seen that the content of four components in the peony kernel samples from Shandong, Henan, Anhui, and Jiangsu is similar, while the content of four components in the peony kernel samples from Dahua Yellow Peony and the four production areas is significantly different; The content of palmitic acid and oleic acid in the Dahuahuang peony samples is twice that of the peony samples from the four production areas, while the content of linoleic acid and linolenic acid is only half that of the peony samples. Linoleic acid and linolenic acid belong to unsaturated fatty acids and are important influencing factors in evaluating the quality of finished oil. The low content of unsaturated fatty acids in the Dahua Huangmu sample indicates that the quality of its seed oil is lower than that of peony varieties, which needs further investigation.

According to the DPPH free radical scavenging rate and Fe3+reduction ability measurements, the antioxidant activity of the seed coat of Dahuahuang peony is significantly higher than that of several peony samples from other production areas. Dahua Huangmudan grows in high-altitude areas, and its ultraviolet radiation is stronger than that in inland areas. Does it produce a large amount of active ingredients in the seed coat that can resist strong ultraviolet radiation, such as flavonoids, anthocyanins, and astragalus? The antioxidant effect of these ingredients may be the reason for the high antioxidant activity of Dahua Huangmudan seed coat. The free radical scavenging rate of Dahuahuang peony seed oil is 30.14%, which is close to 27.33% for peonies produced in Henan. The scavenging rates of peonies produced in Shandong and Anhui are less than 20.00%, and only the scavenging rate of peonies produced in Jiangsu (37.56%) is higher than that of Dahuahuang peony; The results of Fe3+reduction ability determination showed that although the reduction ability of Dahuahuang peony seed oil was the highest, at 0.24Abs, it was not significantly different from the determination results of peony samples from other production areas. Therefore, it can be seen that the antioxidant activity of Dahuahuang peony seed oil is not significant compared to peony.
Peony seed oil has no acute toxicity, genetic toxicity, or subacute toxicity, and has high safety for consumption. Therefore, peony seed oil is known by nutritionists as the “best oil in the world”. Linoleic acid is an important nutrient required by the human body, and peony seed oil is rich in linolenic acid, which has broad development prospects. Vitamin E and squalene in peony seed oil have strong antioxidant effects, while functional fatty acids and sterols and other active substances also have the ability to scavenge free radicals. These components may be the source of peony seed oil’s antioxidant activity. Research has found that peony seed oil is easily absorbed by the skin and can be widely used in the field of food and cosmetics. It has anti-aging, UV protection, anti-inflammatory and other functions; During the production process of peony seed oil, a large amount of by-products are also produced, such as peony seed cakes with high protein and medicinal ingredient content. At present, it has been deeply processed into peony protein powder, peony nutrition stick, and peony snack food. The medicinal ingredients such as linolenic acid, linoleic acid, paeonol, and paeoniflorin contained in the seed cake can be purified and used as pharmaceutical raw materials. Peony seed coat has good antioxidant effects, and its products have been applied in the fields of pharmaceuticals, health products, and cosmetics. From this, it can be seen that further processing the seeds of Dahua yellow peony into high value-added products with long-term economic benefits will inevitably generate good economic and social benefits.