Simultaneous Determination of Seven Flavonoids in Dan Bamboo Phyllostachys glauca McClure Leaf Extract and in Commercial Products by HPLC-DAD

Flavonoids are a group of polyphenolic compounds with health-related properties. The leaves of Phyllostachys glauca McClure are rich in flavonoids and its extracts and extract products are the functional ingredients in several commercial products, such as food additives. A new high-performance liquid chromatography (HPLC) technique was developed and used to analyze seven flavonoids in commercial extract products and P. glauca McClure leaf extract. The leaf extract was purified using column chromatography with macroporous absorption resin (AB-8) before analysis. After a 2-h hydrolysis, the seven flavonoids were simultaneously quantified using HPLC with an ultraviolet photodiode-array detector at 350 nm. Identification of the seven flavonoids (isoorientin, orientin, vitexin, isovitexin, luteolin-6-C-arabinoside, luteolin and tricin) was confirmed by a liquid chromatography mass spectrometer system. Validation was achieved, proving that this method can be used to determine trace amounts of these seven flavonoids in P. glauca McClure leaf extracts and in commercial extract products.

Practical Applications

Phyllostachys glauca McClure leaf extract has been used as a food-based antioxidant and functional food additive. Many commercial products made from P. glauca McClure leaf are sold in the Chinese market. At present, spectrophotometry is the primary method used to determine flavonoid content in bamboo leaf extract and extract products. However, the results of spectrophotometry are easily affected by the other compounds present in a sample, such as anthocyanosides, phenol acids and other phenol compounds. This study provides a novel high-performance liquid chromatography-photodiode-array detector method, which has been developed for simultaneous quantification of seven flavonoids in commercial extract products and P. glauca McClure leaf extract. The hydrolysis sample preparation process and simultaneous determination of seven flavonoids render this method suitable to routine quality assurance analyses for active ingredients commercial extract products and P. glauca McClure leaf extracts. This is of great importance to the pharmaceutical and food additive industry.