Study On Extraction, Purification And Its Bioactivities Of Flaconoids In Purnella Vulgaris L.

Prunella vulgaris Linn is the dry spike of Prunella vulgaris Linn which belongs to self-heal category. Its name comes from the saying "the grass will die away after the Summer Solstice". Prunella vulgaris L. is a traditional Chinese herbal medicine that has detoxification and detumescence effects. The main active components of Prunella vulgaris L. are triterpenes, steroide, phenylpropanoids, flavonoids, coumarone, essential oils, organic acids etc.Up to now, there is no systematic and detailed studies are found on its extraction, separation, purification and bioactivity, which bring negative effects of utilities and exploitation of active components in Prunella vulgaris L.Our focus in this paper is on the studying of flavonoids, which can enhance the application of Prunella vulgaris L. and provide a useful guideline for investigation of new drugs. The main investigations and experimental results in this paper were listed as follows, respectively:1. The nutrients of Prunella vulgaris L. are analyzed. The results are shown as follows (g/100 g, dry mass):ash 12.55, protein 9.77, total sugar 10.21, reduced sugar 1.32, fats 4.91, total phenols 2.78%. The seven trace elements (Mn,Cu,Mg,Fe,Ca,Zn,Cd) were determined by flame atomic absorption spectrometry (FAAS). The results indicated that Prunella vulgaris L. has plenty of trace elements.2. The Box-Behnken design combined with response surface methodology (RSM) was used to optimize three different extraction methods for total flavonoids from Prunella vulgaris L. The results indicated that the highest extraction yield of flavonoids by heat reflux extraction (HRE) could arrive 5.74% using 20% ethanol as solvent and 1:40 solid to liquid ratio for 3.2 h at the temperature of 97.8℃, which was more efficient than that by ultrasonic-assisted extraction (UAE) and microwaves-assisted extraction(MAE).3. The separating and purifying purpose of the flavonoids from Prunella vulgaris L. was studied and compared with four kinds of macroporous resins including D101, AB-8, NKA-Ⅱand NKA-9. The adsorption rate, desorption rate and adsorption kinetics of each resin were studied, and some technical conditions were sptimized via static and dynamic experiments. The results showed that the weak polar AB-8 macroporous resin was good sorbent of the flavonoids, its adsorption rate and desorption rate were 90.29%and 81.29%, respectively. The optimum conditions for separating and purifying the flavonoids by AB-8 resin were:injecting concentration 3.732 mg/mL, pH=5, injecting velocity 2.0mL/min,40%(v/v) alcohol as desorption solvent, desorption velocity of flow 1.5 mL/mL and elution volume 5 BV. The content of flavonoids in the purified extracts reached 81.58%from about 46.25%in the crude extracts after AB-8 resin in the optimized conditions.4. The antioxidant activities of the purified flavonoids were evaluated in vitro by scavenging capability of DPPH free radical and hydroxyl free radical, reducing power, total antioxidant capability and (3-carotene bleaching test. The results showed that the flavonoids have significant antioxidant activities, which can be used as a source of potential antioxidant.5. The bacillus (Escherichia coli, Staphylococcus aureus and Bacillus subtilis) and fungus (Aspergillus niger and Aspergillus oryzae) were selected to in bacteriostasis experiments in vitro. The effect of inhibiting the microorgansims was determined by the inhibition zone diameter, MIC, MBC test. The results showed that the inhibition of bacillus is better than fungus. It has strong inhibition of Escherichia coli, Staphylococcus aureus and Bacillus subtilis, for MIC are 1.5625 mg/mL,1.5625 mg/mL and 3.125 mg/mL, MBC are 3.125 mg/mL,3.125 mg/mL and 6.25 mg/mL The Prunella vulgaris L. flavonoids were perfect additives which could inhibit some microorganisms.