Two New Phenylpropanoid Compounds from Lilium Brownii and Their Anti-monoamine Oxidase Activity.

Baihe is a commonly used Chinese medicine for the treatment of neurological disorders. Clinically, the bulbs of Lilium brownii are used to act as Baihe. In the study, two new phenylpropanoid compounds including 3-O-acetyl-1-O-caffeoylglycerol (1) and 3-O-acetyl-1-O-p-coumaroylglycerol (2) were isolated from the bulbs of L. brownii. Their structures were identified by spectroscopic method and the effect on monoamine oxidase activity was determined using an enzyme labeling method. The results show 1 and 2 have anti-monoamine oxidase activity with 20.96 % and 22.31 % inhibition rates at 50 µg/ml, respectively.

Two New Isospirostanol-Type Saponins from the Bulbs of Lilium Brownii and Their Anti-Hepatocarcinogenic Activity.

Bulbs of Lilium brownii, commonly known as "Bai-he" in China, serve both edible and medicinal purposes in clinical practice. In this study, two new isospirostanol-type saponins were isolated from L. brownii, and their structures were identified by spectroscopic method, and absolute configurations were elucidated by comprehensive analysis of spectral data obtained from combined acid hydrolysis. Two compounds were finally identified as 3-O-[α-L-rhamnopyranosyl-(1→2)-ß-D-glucopyranoside]-(22R,25R)-5α-spirosolane-3ß-ol (1) and 3-O-{α-L-rhamnopyranosyl-(1→2)-[ß-D-glucopyranosyl-(1→4)]-ß-D-glucopyranoside}-(22R,25R)-5α-spirosolane-3ß-ol (2), respectively. Further, we found that compound 2 significantly suppressed the proliferation of SMMC-7721 and HepG2 cells with IC50 values of 26.3±1.08 µM and 30.9±1.59 µM, whereas compound 1 didn't inhibit both of the two hepatocellular carcinoma. Subsequently, compound 2 effectively decreased the levels of interleukin-1ß and tumor necrosis factor-α and the expression of Bcl-2, and increased the expression of Bax and Caspase-3 proteins. Which indicated that the anti-hepatocellular carcinoma effect of compound 2 involves reducing the level of inflammation and inducing apoptosis.

A comprehensive study on the relieving effect of Lilium brownii on the intestinal flora and metabolic disorder in p-chlorphenylalanine induced insomnia rats.

CONTEXT: The bulb of Lilium brownii F. E. Brown (Liliaceae) (LB) is a common Chinese medicine to relieve insomnia. OBJECTIVE: To investigate the molecular mechanism of LB relieving insomnia. MATERIALS AND METHODS: Insomnia model was induced by intraperitoneally injection p-chlorophenylalanine (PCPA) in Wistar rats. Rats were divided into three groups: Control, PCPA (400 mg/kg, i.p. 2 days), LB (598.64 mg/kg, oral 7 days). The levels of 5-hydroxytryptamine (5-HT), norepinephrine (NE), melatonin (MT), and the expression of GABAA, 5-HT1A and MT receptors, as well as pathological changes in hypothalamus, were evaluated. 16S rDNA sequencing and UPLC-MS/MS were used to reveal the change of the intestinal flora and metabolic profile. RESULTS: The adverse changes in the abundance and diversity of intestinal flora and faecal metabolic phenotype altered by PCPA in rats were reversed after LB treatment, accompanied by the up-regulated levels of 5-HT as 8.14 ng/mL, MT as 16.16 pg/mL, 5-HT1A R and GABAA R, down-regulated level of NE as 0.47 ng/mL, and the improvement of pathological phenomena of cells in the hypothalamus. And the arachidonic acid metabolism and tryptophan metabolism pathway most significantly altered by PCPA were markedly regulated by LB. Besides, it was also found that LB reduced the levels of kynurenic acid related to psychiatric disorders and trimethylamine-N-oxide associated with cardiovascular disease. CONCLUSION: The mechanism of LB relieving insomnia involves regulating flora and metabolites to resemble the control group. As a medicinal and edible herb, LB could be considered for development as a health-care food to relieve increasing insomniacs in the future.

Effects of different drying methods on the chemical constituents of Lilium lancifolium Thunb. based on UHPLC-MS analysis and antidepressant activity of the main chemical component regaloside A.

The Lilium lancifolium Thunb. is a herb with multiple functions in both medicine and food in China, and its extracts have shown antidepressant effects. In this study, fresh bulbs of Lilium lancifolium Thunb. were processed to study the effects of different drying processes on changes in its main chemical components. We found that different drying methods can affect the chemical constituents of the herb. Among these components, Regaloside A has been found as the characteristic component. Here, Cell Counting Kit-8 assay, and Western blotting were used to evaluate the neuroprotective antidepressant effects of Regaloside A. The results showed the cell survival rate was improved, the phosphorylation levels of brain-derived neurotrophic factor, tyrosine kinase receptor B, phosphatidylinositol 3 kinase, protein kinase B, and mammalian target of rapamycin were increased after Regaloside A treatment. In general, different drying methods have a significant influence on the chemical composition of the herb, and Regaloside A may be the main chemical component of the herb. It can alleviate the damage of corticosterone in SH-SY5Y cells, and phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin signaling mediated by brain-derived neurotrophic factor/tyrosine kinase receptor B may play an important role in the neuroprotective antidepressant effects of Regaloside A.

Three Previously Undescribed Chlorophenyl Glycosides from the Bulbs of Lilium regale.

Three previously undescribed chlorophenyl glycosides, (2,4,6-trichloro-3-hydroxy-5-methoxyphenyl)methyl ß-D-glucopyranoside (1), (2,4-dichloro-3,5-dimethoxyphenyl)methyl 6-O-ß-D-glucopyranosyl-ß-D-glucopyranoside (2) and 4-chloro-3-methoxy-5-methylphenyl 6-O-(6-deoxy-ß-L-mannopyranosyl)-ß-D-glucopyranoside (3) were obtained from Lilium regale. The absolute configurations of these new finds were elucidated by comprehensive analyses of spectroscopic data combined with acid hydrolysis derivatization. (2,4-dichloro-3,5-dimethoxyphenyl)methyl 6-O-ß-D-glucopyranosyl-ß-D-glucopyranoside (2) can inhibit the proliferation of lung carcinoma A549 cells with an IC50 value of 29 µΜ.

Metabolome-Based Discrimination Analysis of Five Lilium Bulbs Associated with Differences in Secondary Metabolites.

The bulbs of several Lilium species are considered to be both functional foods and traditional medicine in northern and eastern Asia. Considering the limited information regarding the specific bioactive compounds contributing to the functional properties of these bulbs, we compared the secondary metabolites of ten Lilium bulb samples belonging to five different species, using an ultrahigh-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS)-based secondary metabolomics approach. In total, 245 secondary metabolites were detected; further, more metabolites were detected from purple Lilium bulbs (217 compounds) than from white bulbs (123-171 compounds). Similar metabolite profiles were detected in samples within the same species irrespective of where they were collected. By combining herbal analysis and screening differential metabolites, steroid saponins were considered the key bioactive compounds in medicinal lilies. Of the 14 saponins detected, none were accumulated in the bulbs of L. davidii var. willmottiae, also called sweet lily. The purple bulbs of L. regale accumulated more secondary metabolites, and, notably, more phenolic acid compounds and flavonoids. Overall, this study elucidates the differential metabolites in lily bulbs with varying functions and colors and provides a reference for further research on functional foods and the medicinal efficacy of Lilium species.

Lily bulbs' polyphenols extract ameliorates oxidative stress and lipid accumulation in vitro and in vivo.

BACKGROUND: Polyphenols have the potential to reduce the risk of many metabolic disorders. Lily bulbs are rich in polyphenols; however, their effects on lipid metabolism remain unclear. This study aimed to explore the effects of lily bulbs' polyphenols (LBPs) on oxidative stress and lipid metabolism. RESULTS: A total of 14 polyphenolic compounds in LBPs were identified by high-performance liquid chromatography equipped with diode-array detection mass spectrometry. Total phenolic compound in LBPs was 53.76 ± 1.12 g kg-1 dry weight. In cellular experiments, LBPs attenuated the disruption of mitochondrial membrane potential, impeded reactive oxygen species production, alleviated oxidative stress, and reduced lipid accumulation in oleic acid induced HepG2 cells. In in vivo studies, LBPs significantly inhibited body weight gain, reduced lipid levels in serum and liver, and improved oxidative damage in a dose-dependent manner in mice fed a high-fat diet. Moreover, LBPs ameliorated hepatic steatosis and suppressed the expression of hepatic-lipogenesis-related genes (SREBP-1c, FAS, ACC1, and SCD-1) and promoted lipolysis genes (SRB1 and HL) and lipid oxidation genes (PPARα and CPT-1) in mice fed a high-fat diet. CONCLUSION: It was concluded that LBPs are a potential complementary therapeutic alternative in the development of functional foods to curb obesity and obesity-related diseases, such as metabolic syndrome. © 2021 Society of Chemical Industry.

Immobilization of Purified Pectin Lyase from Pseudomonas putida onto Magnetic Lily Flowers (Lilium candidum L.) Nanoparticles and Applicability in Industrial Processes.

Pectinases are an important class of enzymes distributed in many higher plants and microorganisms. One of these enzymes is pectin lyase which has an important role in industrial applications such as clarification of fruit juices. Pectin lyase was purified with 73% yield from Pseudomonas putida bacteria and was 220.7-fold using three phase precipitation technique. Molecular weight of purified pectin lyase was determined as 32.88 kDa with SDS-polyacrylamide gel electrophoresis. The pectin lyase was immobilized covalently via the L-glutaraldehyde spacer to the cellulosic structures of lily flowers (Lilium candidum L.). The immobilized enzyme was then magnetized by modifying with γ-Fe3O4 nanoparticles and determined the most appropriate immobilization conditions as pH 6 and 30 °C. Purified pectin lyase was connected to magnetized support material after 60 min at the rate of 86.4%. The optimum pH and temperatures for the free and immobilized pectin lyase was found to be 6.0 and 40 °C. pH and thermal stabilities of the free and immobilized pectin lyase enzyme have been preserved at high-low temperatures and pH. The structural characterization of the immobilized pectin lyase was performed by SEM, FT-IR, and XRD chromatographic analyses and it was observed that the support materials structure was appropriated to immobilization with pectin lyase and to modify with Fe3O4 nanoparticles.

Structural characterization of Lanzhou lily (Lilium davidii var. unicolor) polysaccharides and determination of their associated antioxidant activity.

BACKGROUD: The Lanzhou lily (Lilium davidii var. unicolor) is the only Lilium species that is used for both culinary and medicinal purposes in China. Its bulbs contain various bioactive substances, such as polysaccharides, saponins and colchicine. Lanzhou lily polysaccharides are known to have anti-immunity, anti-tumor and anti-oxidation functions. RESULTS: The present study used a Box-Behnken design to optimize the ultrasound-assisted extraction of Lanzhou lily polysaccharides. Compared to other enzymes, trypsin significantly increased the polysaccharide yields, whereas the protein content of polysaccharides extracted with trypsin was the lowest. Monosaccharide mainly includes glucose (> 50%) and mannose (> 10%). 1,1-Diphenyl-2-picrylhydrazyl radical scavenging activity, chelating activity, total antioxidant capacity and hydroxyl radical scavenging activity of Lanzhou lily polysaccharides extracted with trypsin were stronger than those extracted without enzymes (control). Structural characteristics of Lanzhou lily polysaccharides extracted with trypsin and extracted without enzymes were characterized by scanning electron microscopy and nuclear magnetic resonance spectroscopy. When water extracted polysaccharide and trypsin extracted polysaccharide concentrations were 200 µg mL-1 , Raw264.7 proliferation rates were 101.69% and 159.41%, respectively. CONCLUSION: The Lanzhou lily polysaccharide was identified as α-(1 → 6)-d-glucan. Consequently, the effects of both potential antioxidant and proliferative activity of trypsin are significant. © 2020 Society of Chemical Industry.

Characterization of a Cis-Prenyltransferase from Lilium longiflorum Anther.

A group of prenyltransferases catalyze chain elongation of farnesyl diphosphate (FPP) to designated lengths via consecutive condensation reactions with specific numbers of isopentenyl diphosphate (IPP). cis-Prenyltransferases, which catalyze cis-double bond formation during IPP condensation, usually synthesize long-chain products as lipid carriers to mediate peptidoglycan biosynthesis in prokaryotes and protein glycosylation in eukaryotes. Unlike only one or two cis-prenyltransferases in bacteria, yeast, and animals, plants have several cis-prenyltransferases and their functions are less understood. As reported here, a cis-prenyltransferase from Lilium longiflorum anther, named LLA66, was expressed in Saccharomyces cerevisiae and characterized to produce C40/C45 products without the capability to restore the growth defect from Rer2-deletion, although it was phylogenetically categorized as a long-chain enzyme. Our studies suggest that evolutional mutations may occur in the plant cis-prenyltransferase to convert it into a shorter-chain enzyme.

Orthogonal array design for optimization of phenyllactic acid-sodium alginate blend coating and its effect on the browning and quality of minimally processed lily bulbs.

BACKGROUND: In order to develop active packaging of lily products, we for the first time investigated the effects of phenyllactic acid (PLA) incorporated into a sodium alginate (SA)-based coating on the quality of minimally processed lily bulbs stored at 4 °C for 15 days. RESULTS: L9 (34 ) orthogonal array design showed that the optimal concentrations of PLA, SA and glycerinum were 0.03, 0.03 and 0.05 mol L-1 , respectively, to prepare a blend coating. It was noticed that a PLA-SA blend coating treatment could inhibit browning and maintain the firmness and ascorbic acid of minimally processed lily bulbs. Compared with the control, polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonia-lyase (PAL) activities of PLA-SA blend coating treated minimally processed lily bulbs reduced by about 31%, 21% and 29% on the 15th day, respectively. Total phenolic and quinone contents decreased, respectively, by 16% and 55% at the same time. Moreover, PLA-SA blend coating treatment eliminated the accumulation of malonaldehyde (MDA) while inhibiting microbial growth of minimally processed lily bulbs. CONCLUSIONS: These results showed PLA-SA blend coating could effectively maintain quality of minimally processed lily bulbs stored at 4 °C, and it might be a prospective technology. © 2018 Society of Chemical Industry.

Bioaccumulation and sources of metal(loid)s in lilies and their potential health risks.

Dietary intake of metal(loid)s can seriously affect human health, but the levels, the bioaccumulation, sources and related health risks of As, Cd, Cr and Pb in cultivated lilies, particularly for Lilium davidii var. unicolor, remain unresolved. We collected 35 lily samples aged 1-6 years from farmlands of two types of soil (heilu soils and loessal soils) in Qilihe district in 2016 and analysed the concentrations of As, Cd, Cr and Pb in bulbs, the soil-bulb bioaccumulation and the potential sources of these elements in bulbs. Non-carcinogenic and carcinogenic risks by consuming lilies were also assessed. Concentrations of four elements decreased in the order of Cr > Pb > Cd > As, and soil-bulb BCFs in the order of BCFCd > BCFCr > BCFPb > BCFAs. The Cd concentration of bulbs of lilies which grew in heilu soils was statistically higher than that of bulbs of lilies which grew in loessal soils, and the Cd concentration of bulbs of lilies aged 1-3 years was statistically higher than that of bulbs of lilies aged 4-6 years. Levels and soil-bulb BCFs of Cr and Pb of two-bulbed lilies were statistically higher than those of one-bulbed lilies. Farmyard manure may be a primary source of Cd in soil. There existed overall potential non-carcinogenic effects by exposure to the combination of four elements. Dietary intake of Cr posed carcinogenic risks to both adults and children. Non-carcinogenic and carcinogenic risks were higher for adults than children. Concluding, the edible parts of lily were significantly polluted by Cr and Pb but not by As and Cd. The number of bulbs significantly impacted concentrations and soil-bulb BCFs of Cr and Pb, but the reason for which needs further studies. Non-carcinogenic and carcinogenic risks caused by lily consumption should not be neglected.

[Advances in studies on steroidal saponins and their pharmacological activities in genus Lilium].

Genus Lilium plants contain a variety of steroidal saponins, so far at least 82 steroidal saponins have been found in the bulbs of Lilium species, including 13 spirostanol saponins (1-13), 39 isospirostanol saponins (14-52), 7 pseudospirostanol saponins (53-59), and 23 furostanol saponins (60-82). Studies have showed that these steroidal saponins exhibit a wide range of pharmacological activities, including antitumor, antibacterial, antiinflammatory, antioxidant, antidepressant, hepatoprotective, hypoglycemic, sedative-hypnotic effect, and inhibition of cAMP phosphodiesterase and Na⁺-K⁺ ATP, et al. This paper has classified and summarized the 82 steroidal saponins isolated and identified from the bulbs of Lilium species and their correlative biological activities. Also, their structural characteristics and structure-activities relationship have been discussed, which could provide references for further research and application development of Lilium plants.

Prokaryotic expression and action mechanism of antimicrobial LsGRP1C recombinant protein containing a fusion partner of small ubiquitin-like modifier.

Antimicrobial peptides (AMPs) are peptides exhibiting broad-spectrum antimicrobial activities and considered as potential therapeutic agents. LsGRP1C, a novel AMP derived from defense-related LsGRP1 protein of Lilium, was proven to inhibit kinds of bacteria and fungi via alteration of microbial membrane permeability and induction of fungal programmed cell death-like phenomena by in vitro assays using synthetic LsGRP1C. In this study, the prokaryotic production of LsGRP1C recombinant protein containing an N-terminal fusion partner of the yeast small ubiquitin-like modifier (SUMO) was achieved by using optimized Escherichia coli host and purification buffer system, which lead to a high yield of soluble SUMO-LsGRP1C fusion protein. In vitro assay revealed that E. coli-expressed SUMO-LsGRP1C exhibited even better antifungal activity as compared to synthetic LsGRP1C. Meanwhile, the ability of SUMO-LsGRP1C in conducting fungal membrane permeabilization and programmed cell death was verified by SYTOX Green staining and 4',6-diamidino-2-phenylindole staining/terminal deoxynucleotidyl transferase dUTP nick-end labeling assays, respectively, indicating that E. coli-expressed SUMO-LsGRP1C shares identical modes of action with synthetic LsGRP1C. Herein, this E. coli expression system enables the effective and convenient production of antimicrobial LsGRP1C in a form of SUMO-fused recombinant protein.

Bioassay-Guided Isolation of Anti-Inflammatory Components from the Bulbs of Lilium brownii var. viridulum and Identifying the Underlying Mechanism through Acting on the NF-κB/MAPKs Pathway.

The bulbs of Lilium brownii var. viridulum (LB) are commonly used as both traditional Chinese medicines and popular functional food for many centuries in China. Previous studies reported that the extract of lily bulbs exhibited anti-inflammatory activity both in vivo and in vitro, but its active components and associated molecular mechanisms remain elusive. In the present study, using bioassay-guided isolation method, two phenylpropenoid acylglycerols, 1-O-feruloyl-2-O-p-coumaroylglycerol (1) and 1,3-O-diferuloylglycerol (2), were obtained and identified from the chloroform fraction of LB. Both compounds 1 and 2 significantly decreased the production of nitrite oxide (NO) in lipopolysaccharide (LPS)-stimulated mouse macrophage RAW264.7 cells in a dose-dependent manner with half maximal inhibitory concentration (IC50) values of 9.12 ± 0.72 µM and 12.01 ± 1.07 µM, respectively. They also inhibited the production of prostaglandin E2 (PGE2) and several other pro-inflammatory cytokines, such as interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). Furthermore, compounds 1 and 2 downregulated the protein levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). They also inhibited the nuclear translocation of nuclear factor-κB (NF-κB) p65 subunit and suppressed mitogen-activated protein kinases (MAPKs) pathway. Taken these data together, compounds 1 and 2 exhibited anti-inflammatory activities through acting on the NF-κB and MAPKs pathway. This research provides the first evidence on the major bioactive constituents and related molecular mechanisms of LB as an anti-inflammatory agent. Our findings also advanced the understanding of LB as a traditional herbal medicine for the prevention and treatment of inflammation.

[Analysis and evaluation of eight active ingredients in Lilium lancifolium from different regions].

This study established a rapid UPLC-TQ-MS/MS method for determination of eight active ingredients in Lilium lancifolium. The contents range of regaloside E, F, C and B are as follows: 0.604 0×10⁻¹-18.62×10⁻¹, 0.680 0×10⁻²-44.75×10⁻², 0.700 0×10⁻³-29.65×10⁻¹, 0.170 0×10⁻¹-4.724 mg•g⁻¹; the contents of chlorogenic acid, caffeic acid, protocatechualdehyde and ferulic acid, within the range of 6.827×10⁻³-16.07×10⁻³, 0.011 1×10⁻³-79.71×10⁻³, 0.593 7×10⁻³-2.962×10⁻³, 2.606×10⁻²-45.89×10⁻² mg•g⁻¹, respectively. According to PCA (principal components analysis) plotting, 35 batches can be divided into two categories, namely Anhui Huoshan and Hunan Longshan. The main different elements between these two categories are caffeic acid and ferulic acid according to the VIP (variable importance in the projection) points figure. Based on comprehensive principal component values, there are eight batches of L. lancifolium from Huoshan among the comprehensive ranking of ten. The UPLC-TQ-MS method for simultaneous analysis of eight active ingredients is accurate, efficient and convenient. This result can provide scientific basis for quality control of L. lancifolium.

Lilium compounds kaempferol and jatropham can modulate cytotoxic and genotoxic effects of radiomimetic zeocin in plants and human lymphocytes In vitro.

Organisms are constantly exposed to the detrimental effect of environmental DNA-damaging agents. The harmful effects of environmental genotoxins could be decreased in a viable way by antimutagenesis. One of the modern approaches to reduce the mutagenic burden is based on exogenous natural and synthetic compounds that possess protective and antimutagenic potential against genotoxins. The natural compounds kaempferol and jatropham isolated from Lilium candidum were tested with respect to their potential to protect cells against the radiomimetic zeocin, as well as to their cytotoxic and genotoxic activities in two types of experimental eukaryotic test systems: Hordeum vulgare and human lymphocytes in vitro. Mitotic index (MI) was used as an endpoint for cytotoxicity; the frequency of chromosome aberrations (MwA) and the number of induced micronuclei (MN), as endpoints for genotoxicity/clastogenicity. Formation of aberration "hot spots" was also used as an indicator for genotoxicity in H. vulgare. Both kaempferol and jatropham were shown to possess a potential to modulate and decrease the cytotoxic and genotoxic/clastogenic effect of zeocin depending on the experimental design and the test system. Our data could be useful for health research programs, particularly in clarifying the pharmacological potential and activity of natural plant compounds. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 751-764, 2016.

Chemistry and biological activity of steroidal glycosides from the Lilium genus.

Plants from the Lilium genus are a rich source of chemical diversity and have been the focus of natural products chemistry research for over twenty years. This manuscript provides a background on the chemistry and nomenclature of steroidal glycosides, as well as a chronological account of the progress between the years of 1989 up to 2014, with respect to their isolation and characterization from the genus. This review highlights the traditional use of lilies, as both food and medicine, and brings attention to the fact that the genus contains 110 accepted species of which the chemistry and biological activity of the steroidal glycosides from the majority have not been investigated to date. Thus, making the genus a relatively untapped resource that contains a potential treasure trove of chemical diversity waiting to be discovered.

Stereo- and regioselective phyllobilane oxidation in leaf homogenates of the peace lily (Spathiphyllum wallisii): hypothetical endogenous path to yellow chlorophyll catabolites.

Invited for the cover of this issue is the group of Bernhard Kräutler at the University of Innsbruck, Austria. The image depicts the autumnal "disappearance" of chlorophyll and the ensuing rapid formation of colorless phyllobilins. Read the full text of the article at 10.1002/chem.201404783.

Stereo- and regioselective phyllobilane oxidation in leaf homogenates of the peace lily (Spathiphyllum wallisii): hypothetical endogenous path to yellow chlorophyll catabolites.

In senescent leaves, chlorophyll typically is broken down to colorless and essentially photo-inactive phyllobilanes, which are linear tetrapyrroles classified as "nonfluorescent" chlorophyll catabolites (NCCs) and dioxobilane-type NCCs (DNCCs). In homogenates of senescent leaves of the tropical evergreen Spathiphyllum wallisii, when left at room temperature and extracted with methanol, the major endogenous, naturally formed NCC was regio- and stereoselectively oxidized (in part) to a mixture of its 15-hydroxy and 15-methoxy derivative. In the absence of methanol in the extract, only the 15-OH-NCC was observed. The endogenous oxidation process depended upon molecular oxygen. It was inhibited by carbon monoxide, as well as by keeping the leaf homogenate and extract at low temperatures. The remarkable "oxidative activity" was inactivated by heating the homogenate for 10 min at 70 °C. Upon addition of a natural epimeric NCC (epiNCC) to the homogenate of senescent or green Sp. wallisii leaves at room temperature, the exogenous epiNCC was oxidized regio- and stereoselectively to 15-OH-epiNCC and 15-OMe-epiNCC. The identical two oxidized epiNCCs were also obtained as products of the oxidation of epiNCC with dicyanodichlorobenzoquinone (DDQ). Water elimination from 15-OH-epiNCC occurred readily and gave a known "yellow" chlorophyll catabolite (YCC). The endogenous oxidation process, described here, may represent the elusive natural path from the colorless NCCs to yellow and pink coloured phyllobilins, which were found in (extracts of) some senescent leaves.