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With hot water extraction and ethanol precipitation, three high molecular weight polysaccharides, LZLs (LZL-1, LZL-2 and LZL-3), were successfully purified from the edible bulbs of Lanzhou lily by DEAE-52 cellulose and sephadex G-200 column. The structure features of LZLs were characterized by gas chromatography, scanning electron microscope, high performance gel-permeation chromatography, IR and NMR, and the antioxidant activities of LZLs were assayed. The results showed that LZL-1, LZL-2 and LZL-3 were composed of glucose and mannose with the molar ratios of 2.4:2.5, 2.6:2.5 and 2.2:2.5, while their molecular weights were 2.33 × 106, 1.92 × 106 and 1.26 × 106, respectively. LZLs were mainly α-pyranose configurations with lamellar structure and triple helix conformation except LZL-3. LZLs had similar glycosidic linkage patterns with main substitution at O-6 of glucose or mannose but the different substitution positions at O-3 of them. Vitro bioassays showed that LZLs had effective scavenging abilities to free radicals, especially to DPPH and hydroxyl radicals. When the concentration reached 4 mg/mL, the scavenging rate of LZLs to DPPH and hydroxyl radicals were up to 60% and 70%, respectively. These findings provided more references for potential applications of Lanzhou lily polysaccharides as natural antioxidant agents in food and pharmaceuticals. [ABSTRACT FROM AUTHOR]

The present research aimed to further identify the fine structure, morphology, and thermal behaviors of a galactoglucan BHP-2 derived from Lanzhou lily bulbs through partial acid hydrolysis, methylation, 2D NMR (1H 1H COSY, HSQC, and HMBC), scanning electron microscopy (SEM) and thermogravimetric-differential thermal analysis (TG-DTA). Additionally, the study assessed the potential in vitro hypoglycemic effect of BHP-2 by examining its inhibitory effect on α -glucosidase and α -amylase. The results indicated that the main backbone composition of BHP-2 consisted of →4)- α -D-Glc p -(1→, →3)- β -D-Glc p -(1 → and →6)- β -D-Gal p -(1→, while the side chain composition predominantly featured →4)- α -D-Glc p -(1→, →3,5)- α -L-Ara f -(1 → and →3)- β -D-Gal p -(1→, attached to the C-2 and/or C-3 positions of →4)- α -D-Glc p -(1→. Terminal residues consisted of α -D-Glc p -(1 → and β -L-Ara f -(1→. BHP-2 exhibited excellent thermal stability, with a microscopic surface characterized by tightly packed sheets and numerous spiral depressions, which might contribute to its remarkable in vitro hypoglycemic effect. BHP-2 showed competitive inhibition of α -amylase and mixed non-competitive inhibition of α -glucosidase, with respective IC50 values of 0.31 and 0.18 mg/mL, closely resembling to those of acarbose (0.27 and 0.12 mg/mL). These findings suggested that BHP-2 had potential as an additive for glycemic intervention. [ABSTRACT FROM AUTHOR]

Two heteropolysaccharides, BHP-1 and BHP-2, were separated and purified from the edible bulbs of Lilium davidii var. unicolor Cotton by anion-exchange and gel-permeation chromatography. The primary structural characteristics of BHP-1 and BHP-2 were investigated by Congo red test, X-ray diffractometry (XRD) analysis, IR, GC and NMR. The results showed that the weight-average molecular weight (M W) and number-average molecular weight (Mn) of BHP-1 and BHP-2 were nearly 1.93 × 105 g/moL, 8.86 × 104 g/moL and 3.52 × 104 g/moL, 2.95 × 104 g/moL, respectively. Glucose and mannose comprised BHP-1 in a relative molar ratio of 5.9:2.0, and BHP-2 was consisted of glucose, galactose, mannose and arabinose with approximate molar ratios of 8.3:1.5:1.0:1.1. Their backbone mainly contained α-(1 → 4)-linked d -glucopyranosyl. In addition, the C-6 of the glucose and C-2 of mannose residue of BHP-1 and BHP-2 were substituted. The two polysaccharides were semi-crystalline substance with multi-branching structure and triple helix conformation. Bioassays showed that BHP-1 and BHP-2 had effective antioxidant activities evaluated by DPPH, scavenging superoxide radical and OH radical in a dose-dependent manner. The two heteropolysaccharides also displayed distinct and selective antibacterial activity against B. cereus , P. putida , M. luteus and K. pneumonia with inhibition zones of 13 mm, 16 mm, 17 mm, 23 mm and 12 mm, 17 mm, 19 mm, 20 mm, respectively. These findings provided a reference for potential applications of the polysaccharides from L. davidii as natural antioxidants and antibacterial agents in food and pharmaceuticals. Unlabelled Image • First report on the structure and activity of the polysaccharide by the 70% ethanol precipitation from Lanzhou lily. • Two polysaccharides purified with anion-exchange and gel-permeation chromatography from Lanzhou lily. • Two polysaccharides had effective antioxidant activities in vitro. • Two polysaccharides had distinct and selective antibacterial activity against test bacteria. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Compounds from the rhizosphere soil of Lanzhou lily were isolated and identified. • Phytotoxic activities of the compounds were evaluated and primary allelochemicals were clarified. • Concentrations of allelochemicals in the rhizosphere soil were quantified. Abstract Lanzhou lily (Lilium davidii var. unicolor) is a perennial plant with medical and edible dual purpose in China and mainly planted in the middle area of Gansu province as a bulb crop. Like many other plants of the genus Lilium , the yield and quality of Lanzhou lily have been severely hampered by replanting failure during the cultivation. Previous reports showed that aqueous extractions of different organs from Lilium plants influenced the seed germination and seedling growth of several target plants. But the specific compounds which are responsible for the phytotoxicity remain obscure. In this study, six compounds were isolated and elucidated from the rhizosphere soil of Lanzhou lily. Among them, dibutyl phthalate, decyl trans - p -coumarate, 7-oxo-sitosterol, 6-hydroxystigmast-4-en-3-one and β-sitosterol-3- O -glucoside, observably inhibited the growth of Lactuca sativa and Lanzhou lily seedlings, were clarified as main allelochemicals. They were further confirmed and quantified in the rhizosphere by high-performance liquid chromatography (HPLC), with a total concentration of 117.36 μg/g (dry soil). These findings provide allelopathic evidence of Lanzhou lily, which may be helpful for clarifying the replanting problems of Lilium plants. [ABSTRACT FROM AUTHOR]