Quinolizidine-Based Variations and Antifungal Activity of Eight Lupinus Species Grown under Greenhouse Conditions.

Fusarium oxysporum is an aggressive phytopathogen that affects various plant species, resulting in extensive local and global economic losses. Therefore, the search for competent alternatives is a constant pursuit. Quinolizidine alkaloids (QA) are naturally occurring compounds with diverse biological activities. The structural diversity of quinolizidines is mainly contributed by species of the family Fabaceae, particularly the genus Lupinus. This quinolizidine-based chemo diversity can be explored to find antifungals and even mixtures to address concomitant effects on F. oxysporum. Thus, the antifungal activity of quinolizidine-rich extracts (QREs) from the leaves of eight greenhouse-propagated Lupinus species was evaluated to outline promising QA mixtures against F. oxysporum. Thirteen main compounds were identified and quantified using an external standard. Quantitative analysis revealed different contents per quinolizidine depending on the Lupinus plant, ranging from 0.003 to 32.8 mg/g fresh leaves. Bioautography showed that all extracts were active at the maximum concentration (5 µg/µL). They also exhibited >50% mycelium growth inhibition. All QREs were fungistatic except for the fungicidal QRE of L. polyphyllus Lindl. Angustifoline, matrine, 13α-hydroxylupanine, and 17-oxolupanine were ranked to act jointly against the phytopathogen. Our findings constitute reference information to better understand the antifungal activity of naturally afforded QA mixtures from these globally important plants.

Quinolizidine Alkaloids with Antiviral and Insecticidal Activities from the Seeds of Sophora tonkinensis Gagnep.

The discovery of novel, effective, and botanical pesticides is one of the main strategies for modern plant protection and insect pest control. During the search for novel botanical pesticides from natural sources, the seeds of Sophora tonkinensis were systematically investigated to obtain 11 new matrine-type alkaloids (1-11), including one novel matrine-type alkaloid featuring an unprecedented 5/6/6/6 tetracyclic skeleton (1), along with 16 known compounds (12-27). Their structures were elucidated by comprehensive spectroscopic data analysis (IR, UV, NMR, and HRESIMS), ECD calculations, and single-crystal X-ray diffraction. The anti-tobacco mosaic virus (TMV) activity and insecticidal activities against Aphis fabae and Tetranychus urticae of the compounds were also respectively screened using the half-leaf method and spray method. Biological tests indicated that compounds 2, 4, 6, and 26 displayed significant anti-TMV biological activities compared with the positive control ningnanmycin. Compounds 7, 17, and 26 presented moderate activities against A. fabae with LC50 values of 38.29, 18.63, and 23.74 mg/L, respectively. Moreover, compounds 13 and 26 exhibited weak activities against T. urticae.

Effect of Ultrasound Application on Protein Yield and Fate of Alkaloids during Lupin Alkaline Extraction Process.

The objective of this work is to elucidate the fate of quinolizidine alkaloids (QA) during the lupin protein extraction process assisted with ultrasound and the evaluation of the nutritional and functional properties of the protein fraction. Proximal characterization, concentration of anti-nutritional compounds, amino acid profile and protein solubility profile of flours from three lupin species were (L. albus, L. angustifolius and L. mutabilis) assessed. The result showed a significant difference (p < 0.05) in protein concentration, fat, total alkaloids and particle size between the three species flours. Based on these parameters, the most different Lupinus species (L. mutabilis and L. angustifolius) were chosen to study the behavior of the protein fraction in terms of functionality, composition and resistance to thermal treatments. The results obtained for L. mutabilis described the ultrasound effect as beneficial for protein yield (14% more than control), QA reduction from bagasse (81% less than control) and protein isolate production (50% less than control). On the other hand, L. angustifolius was more resistant to the ultrasound effect with no significant difference between treatments (10 and 15 min) and control but with the lower toxicity and better amino acid score. These results will be useful to design processes to assist in the objective of meeting the future protein demand of the population.

A simple and fast quantitative analysis of quinolizidine alkaloids and their biosynthetic precursor, lysine, in Sophora alopecuroides by hydrophilic interaction chromatography coupled with triple-quadrupole tandem mass spectroscopy.

INTRODUCTION: Different parts of Sophora alopecuroides L. (Fabaceae) have historically been used in traditional Chinese medicine for the treatment of dysentery and enteritis. This plant is also utilised as an important resource for industrial preparation of quinolizidine alkaloidal pharmaceuticals. OBJECTIVE: Establish a reliable, simple and fast analytical method for the quantitative determination of the quinolizidine-type alkaloids and extend understanding of the metabolism of quinolizidine-type alkaloids in S. alopecuroides. METHODS: Hydrophilic interaction chromatography coupled with triple-quadrupole tandem mass spectrometry (HILIC-TQ-MS/MS) in multiple-reaction monitoring (MRM) mode were used to determine seven quinolizidine-type alkaloids and their biosynthetic precursor, lysine, in S. alopecuroides. RESULTS: A good separation was obtained on an ultra high-performance liquid chromatography (UHPLC) amide column within 7 min. The overall limits of detection (LODs) were between 1.13 and 2.81 ng/ml, and limits of quantitation (LOQs) were between 3.80 and 8.48 ng/ml. The developed method was successfully applied to 21 samples of S. alopecuroides. The seeds had the highest concentration of alkaloids among the different plant parts. Oxymatrine and oxysophocarpine were the two most abundant alkaloids in all of the different parts and at different phenological growth stages. The contents of quinolizidine alkaloids showed correlations with lysine. CONCLUSION: A rapid and sensitive analytical method was established for the simultaneous determination of seven quinolizidine-type alkaloids and their biosynthetic precursor, lysine, in S. alopecuroides; the content of lysine may be used as a marker to predict alkaloid production.

Microclimatic variation in UV perception and related disparity in tropane and quinolizidine alkaloid composition of Atropa acuminata, Lupinus polyphyllus and Hyoscyamus niger.

The aim of current research was to evaluate the physiological adjustment in three medicinal herbs viz., Atropa acuminata, Lupinus polyphyllus and Hyoscyamus niger to the winter period characterised by intense UV flux in Kashmir valley across the North Western Himalaya. Quinolizidine (QA) and tropane alkaloid (TA) concentrations were analysed in these herbs thriving at two different altitudes via GC-MS and correlated by PCA analysis. This study investigated the hypothesis that UV reflectance and absorbance at low temperatures are directly related to disparity in alkaloid accumulation. Among QAs in L. polyphyllus, ammodendrine and lupanine accumulated at higher concentration and exhibited significant variation of 186.36% and 95.91% in ammodendrine and lupanine respectively in both sites. Tetrahydrohombifoline displayed non-significant variation of about 9.60% irrespective of sites. Among tropane alkaloid (TA), hyoscyamine was recorded as the most abundant constituent irrespective of the plant and site while apotropine accumulated in lesser quantity in A. acuminata than H. niger. However, apotropine demonstrated significant variation of 175% among both sites. The final concentration of quinolizidine (QA) and tropane alkaloid (TA) reflects the interplay between reflectance and absorbance of UV radiation response field. These findings suggest that spectral response of UV light contributes directly to alkaloid biosynthesis.

Assessing the genotoxicities of sparteine and compounds isolated from Lupinus mexicanus and L. montanus seeds by using comet assay.

The genus Lupinus is widely distributed. Its seeds are used for animal and human food, and Lupinus possesses pharmacological potential because of its high content of quinolizidine alkaloids and flavonoids; however, there is little available information about its genotoxicity. We used the comet assay and staminal nuclei of Tradescantia (clone 4430) to evaluate the in vitro genotoxicity of 4 concentrations (0.01, 0.1, 0.5, and 1.0 mM) of alkaloid extracts of Lupinus mexicanus and Lupinus montanus, flavonoids of L. mexicanus, and commercial sparteine; nitrosodiethylamine was used as a positive control and untreated nuclei were used as a negative control. All concentrations of L. mexicanus and L. montanus showed significant genotoxic activity (P ≤ 0.05). A similar behavior was observed for flavonoid extracts of L. montanus except the 1.0 mM concentration. Sparteine showed genotoxic activity only at 0.5 mM. The order of genotoxicity of the compounds studied was as follows: L. mexicanus > L. montanus > flavonoids of L. montanus > sparteine. There is evident genotoxic activity in the compounds that were studied, particularly at lower concentrations (0.01 and 0.1 mM). Given the limited information about the genotoxicity of the compounds of L. mexicanus and L. montanus, further studies are necessary.

Quinolizidine alkaloids from Sophora velutina subsp. zimbabweensis (Fabaceae: Sophoreae).

Three novel quinolizidine alkaloids, N-methylenehydroxycytisine (1), 6,7-dihydroxylupanine (2), and velutinine (3) have been isolated from the fruits and pods (1 and 2) and stem bark (3) of Sophora velutina subsp. zimbabweensis along with the known quinolizidine alkaloids, 7-hydroxylupanine (4), thermopsine (5), N-methylcytisine (6), cytisine (7), an aromatic ester, methyl-3-(3',4'-dimethoxyphenyl)-2-propenoate (8) and the triterpenoids, lup-20(29)-ene-3beta-ol (9) and 12-oleanen-3-one (10). Compounds 6 and 10 showed good antibacterial activity against E. faecalis, with MIC values of 20.8 and 10.9 microg mL(-1), respectively. The other compounds tested exhibited low to moderate antibacterial activity.

Biphenyl and biphenyl ether quinolizidine N-oxide alkaloids from Lagerstroemia indica L.

Four new biphenyl and biphenyl ether quinolizidine N-oxide alkaloids, 5- EPI-dihydrolyfoline N-oxide (1), decamine N-oxide (2), lagerstroemine N-oxide (3), and lagerine N-oxide (4), were isolated from the aerial parts of Lagerstroemia indica, and their structures were established by extensive spectroscopic studies. In addition, the inhibitory effects of isolated compounds on rat lens aldose reductase (RLAR) were examined.

Determination of quinolizidine alkaloids in different Lupinus species by NACE using UV and MS detection.

Lupin seeds are important for animal and human nutrition. However, they may contain toxic quinolizidine alkaloids (QA). Analytical methods for a reliable alkaloid determination are therefore of importance. Here the presented study reports on the first CE method for the analysis of QA in Lupinus species. A buffer system consisting of 100mM ammonium formate in methanol, acetonitrile, and small amounts of water and acetic acid enabled the baseline separation of sparteine, lupanine, angustifoline and 13alpha-hydroxylupanine in less than 10min. Applied voltage, temperature and detection wavelength were 25kV, 30 degrees C and 210nm, respectively. Additional compounds were identified in CE-MS experiments, in which all alkaloids could be assigned in positive ESI mode at corresponding [M+H](+) values. The CE method was validated for linearity, sensitivity, accuracy and precision, and then used to assess the seeds of seven different Lupinus species for their alkaloid content. Lupanine was present in all of them within a range from 0.02% (L. densiflorus, L. microcarpus) to 1.47% (L. albus). The highest percentage of an individual alkaloid was found in L. polyphyllus (3.28% of angustifoline), the content of total alkaloids ranged from 0.43% (L. microcarpus) to 5.13% in L. polyphyllus. The quantitative results were in good agreement with literature data.

Alkaloids from Sophora flavescens Aition.

Although the quinolizidine alkaloids and flavonoids, the main active components of the traditional Chinese medicine Sophora flavescens, have been largely investigated, a new matrine alkaloid derivative 9alpha-hydroxy-7,11-dehydromatrine (1) and a rare 1,4-diazaindan-type alkaloid flavascensine (17), together with 15 known alkaloids, were isolated from S. flavescens. The structures were established on the basis of spectroscopic techniques.

Herbal plants as a promising source of natural antifoulants: evidence from barnacle settlement inhibition.

A series comprising hexane, ethyl acetate, ethanol and aqueous extracts from six common Chinese herbs (Carpesium abrotanoides, Melia toosendan, Cnidium monnieri, Vitex negundo, Stemona sp. and Sophora flavescens) was investigated for antifouling (AF) activity against cypris (cyprids) larvae of the barnacle Balanus albicostatus. All extracts tested except the aqueous extract from Stemona sp. significantly inhibited the settlement of cyprids, the most potent being the ethyl acetate extract of S. flavescens (EC(50) value 2.08 microg ml(-1)), from which an AF compound, identified as 2'-methoxykurarinone, was isolated using bioassay-guided procedures. Furthermore, the AF activity of this compound was found to be highly reversible and greater than that of the three other natural products from S. flavescens, namely matrine, oxymatrine and oxysophocarpine. These compounds have been used commercially in China for their pharmaceutical activities, but their AF activities have not previously been evaluated. Analysis of structure-activity relationships suggested that the N-1 nitrogen atom in matrine plays a crucial role in AF activity. Overall, the present findings indicate that herbal plants are a valuable source of novel AF agents.

Microemulsion electrokinetic chromatography coupling with field amplified sample injection and electroosmotic flow suppressant for analysis of some quinolizidine alkaloids.

A new rapid and reproducible method using microemulsion electrokinetic chromatography (MEEKC) combining field amplified sample injection and electroosmotic flow suppressant for the analysis of five quinolizidine alkaloids is developed in this paper. For the separation of five quinolizidine alkaloids, a running buffer composed of 1.2% (v/v) 1-butanol, 0.6% (v/v) ethyl acetate and 98.2% (v/v) 1 mM Na(2)B(4)O(7)-2 mM NaH(2)PO(4) buffer solution containing 21 mM sodium cholate (SC) (pH 6.5) was developed. The resolution of the analytes was improved significantly by adding a divalent cation (e.g., Mg(2+)) to the running buffer as an electroosmotic flow modification. In order to analyze trace quinolizidine alkaloids in traditional Chinese herbal medicines, field amplified sample injection (FASI) was applied to increase the detection sensitivity. The detection limits (defined as S/N=3) for the analytes could be as low as 0.0001 microg/mL. This method was applied for the determination of quinolizidine alkaloids in real samples with simple extraction procedures, and the assay results were satisfactory.

Alkaloids from Daphniphyllum oldhami.

Four new Daphniphyllum alkaloids, daphnioldhanines H-K ( 1- 4), along with 34 known alkaloids, were isolated from Daphniphyllum oldhami. The known alkaloid dehydrodaphnigraciline ( 5) is now reported as a natural product. Their structures were elucidated by spectroscopic methods, especially 2D NMR techniques. The effects against platelet aggregation of compounds 1, 3, and 5 were evaluated, and 3 showed stronger activity against platelet aggregation induced by PAF. This is the first report of quinolizidine alkaloids from the genus Daphniphyllum.