Three new taxane diterpenoids from seeds of the Chinese yew, Taxus yunnanensis and T. chinensis var. mairei

Three new taxane diterpenoids were isolated from the seeds of the Chinese yew, Taxus yunnanensis Cheng et L. K. Fu and T. chinensis var. mairei Cheng et L. K. Fu. The structures were established as 1beta,10beta-dihydroxy-9alpha,13alpha-diacetoxy-5alpha-(3'-dimethylamino-3'-phenyl)-propionyloxytaxa-4(20),11-diene, 5alpha-hydroxy-9alpha,100,13alpha-triacetoxy-11(15-->1)abeotaxa-4(20),11-di-ene, and 5alpha,13alpha-dihydroxy-9alpha,10beta-diacetoxy-11 (15-->1 )abeo-taxa-4(20),11-diene on the basis of 1D, 2D NMR, and mass spectral analysis.     

Two new dammarane triterpene glycosides from the rhizomes of Panax notoginseng

Two new dammarane triterpene glycosides named notoginsenosides Rw 1 (1) and Rw 2 (2) were isolated from the rhizomes of Panax notoginseng, together with 20 known compounds including protopanaxadiol (3), protopanaxatriol (4), ginsenosides Rb1 (5), Rd (6), Re (7), Rg1 (8), Rg2 (9), 20-(S)-Rg3 (10), 20-(R)-Rg(3) (11), Rh1 (12), Rh4 (13), Rf (14), 20-O-glucopyranosyl Rf (15), notoginsenosides R1 (16), R2 (17), T5 (18), S (19), T (20), and Fa (21), and koryoginsenoside R1 (22). Based on FABMS, HRFABMS, IR, (1)H, 13C, and 2D-NMR (HSQC, HMBC, and COSY) spectral data, the structures of the new compounds were elucidated as 6-O-beta-d-xylopyranosyl-20-O-beta-d-xylopyranosyl-(1 --> 6)-beta-d-glucopyranosyldammar-24-ene-3beta,6alpha,12beta,20(S)tetraol (1) and 6-O-beta-d-xylopyranosyl-(1 --> 2)-beta-d-glucopyranosyldammar-22-ene-(trans)-3beta,6alpha,12beta,20(S), 25-pentaol (2). Compounds 3, 4, 13, and 22 were isolated from P. notoginseng for the first time.     

Terpenoids and steroids from several euphorbiaceae and pinaceae plants]

During the course of a search for biologically active constituents from unexamined plant sources, several biogenetically interesting new di- and tri-terpenes and steroids were isolated from several weeds and shrubs of Euphorbiaceae and the bark, leaves and cones of several Pinaceae trees which had been treated as wastes in the forestry industry. Euphorbia supina contained 3,4-seco-5 alpha- and 5 beta-adian-4(23)-ene-3,5-diols and related oxides, oxygenated fern-8-en-3 beta-ols named supinenolones A-E and unusually migrated oxyfernanes having (9S)- and (9R)-7(8-->9)abeo-9-D:C-friedo-B':A'-neogammacerane skeletons named spirosupinane and neospirosupinane, while E. chamaesyce contained 3,4-seco-oleana-4(23), 18-dien-3-oic acid, 3,4-seco-8 beta H-ferna-4(23),9(11)-dien-3-oic acid and two oxygenated obtusifoliols. The bark of Phyllanthus flexuosus (Euphorbiaceae) contained 11 beta-hydroxy-D:A-friedo-olean-1-en-3-one, lup-20(29)-ene-3 beta, 15 alpha-diol, olean-12-ene-3 beta,15 alpha-diol and olean-12-ene-3 beta,15 alpha,24-triol together with trichadenic acid B for which we revised the structure to 3 beta-hydroxy-D:A-friedo-oleanan-27-oic acid. Two 26-nor-D:A-friedo-olean-14-enes were isolated from P. watsonii. Regarding Pinaceae trees, an unusually migrated abieslactone [(3R, 7S, 9R, 23R)-7-hydroxy-3-methoxy-8-oxo-7(8-->9)abeo-lanost-24-eno-26,23-lactone], named spiroveitchionolide, was isolated from the bark of Abies species, besides nine abieslactone analogues. Two pairs of unusually migrated serratanes, piceanonols A and B and jezananals A and B having novel skeletal systems of 14(13-->12) abeo- and 16(15-->14) abeo-serratanes named piceanane and jezanane, respectively, were also isolated from the stem bark of Picea species, besides three 14 beta,15 beta-epoxyserratanes and two 13 alpha,14 alpha-epoxyserratanes. The leaves of Larix kaempferi contained two deformed abietanes named karamatsuic acid (9,10-seco-9,10 alpha-epoxyabieta-8,11,13-trien-18-oic acid) and larikaempferic acid [9 alpha,13 alpha-epoxy-8-oxo-9(8-->7)abeo-7 beta-abietan-18-oic acid], as well as the cones to contain 8 alpha,12 alpha-epidioxy-15-hydroxyabiet-13-en-18-oic acid, three diepoxy-abietan-18-oic acids and two new dehydroabietic acid analogues. Several of the above compounds exhibited inhibitory effects against tumor-promoting and DNA topoisomerase II activities.     

Cycloetherification of hydroxyoleanenes by N-bromosuccinimide

Treatment of 28-hydroxyolean-12-enes with N-bromosuccinimide (NBS) in acetonitrile at room temperature afforded 12 alpha-bromooleanan-13beta, 28-epoxides in high yield. This reaction resulted in the formation of olean-9 (11), 12-diene-18alpha, 29-epoxides from 29-hydroxy isomers but recovered only starting materials from 30-hydroxy isomers. NBS will be used a reagent for diagnostic tool to distinguish between isomers bearing a primary hydroxyl group on D/E rings of olean-12-enes.     

Bioactive terpenes from the roots of Chloranthus henryi

12,15-Epoxy-5alpha H,9beta H-labda-8(17),13-dien-19-oic acid (1) and 14-methoxy-15,16-dinor-5alpha H,9alpha H-labda-13(E),8(17)-dien-12-one (2), two new labdane-type diterpenes, and 1alpha-hydroxy-8,12-epoxyeudesma-4,7,11-triene-6,9-dione (3), one new eudesmane-type sesquiterpene, were isolated from Chloranthus henryi Hemsl, along with two known compounds, 8beta H-eudesma-4(14),7(11)-dien-12,8-olide (4) and 8beta-hydroxyeudesma-4(14),7(11)-dien-12,8-olide (5). Their structures were established by a combination of 1D- and 2D-NMR spectroscopic techniques. The new compounds 2, 3 and the known compound 4 exhibited antitumor activities against Hela and K562 human tumor cell lines.     

Anti-inflammatory ergostanes from the basidiomata of Antrodia salmonea

Three new anti-oxidative ergostanes, methyl antcinate L (1), antcin M (2), and methyl antcinate K (3), together with nine additional known compounds, 3-ketodehydrosulphurenic acid, sulphurenic acid, dehydrosulphurenic acid, 3beta,15alpha-dihydroxylanosta-7,9(11),24-trien-21-oic acid, zhankuic acid A, zhankuic acid B, zhankuic acid C, antcin C, and antcin K were isolated from the basidiomata of Antrodia salmonea, a newly identified species of Antrodia (Polyporaceae) in Taiwan. These three new compounds were identified as methyl 3alpha,7alpha,12alpha-trihydroxy-4alpha-methylergosta-8,24(29)-dien-11-on-26-oate (1), 3alpha,12alpha-dihydroxy-4alpha-methylergosta-8,24(29)-dien-11-on-26-oic acid (2), and methyl 3alpha,4beta,7beta-trihydroxy-4alpha-methylergosta-8,24(29)-dien-11-on-26-oate (3) by spectroscopic analysis. We studied their antioxidative potential on the production of reactive oxygen species and nitric oxide (NO) in neutrophils and microglial cells, respectively. Compounds 1-3 displayed potent antioxidative activity with IC50 values of around 2.0-8.8 microM that was partially due to inhibition (6-67%) of NADPH oxidase activity but not through direct radical-scavenging properties. Compounds 1-3 also inhibited NO production with IC50 values of around 1.7-16.5 microM and were more potent than a non-specific NOS inhibitor. We conclude that these three new compounds 1, 2, and 3 exhibit anti-inflammatory activities in activated inflammatory cells.     

Search for constituents with neurotrophic factor-potentiating activity from the medicinal plants of paraguay and Thailand

20 medicinal plants of Paraguay and 3 medicinal plants of Thailand were examined on nerve growth factor (NGF)-potentiating activities in PC12D cells. The trail results demonstrated that the methanol extracts of four plants, Verbena littoralis, Scoparia dulcis, Artemisia absinthium and Garcinia xanthochymus, markedly enhanced the neurite outgrowth induced by NGF from PC12D cells. Furthermore, utilizing the bioactivity-guided separation we successfully isolated 32, 4 and 5 constituents from V. littoralis, S. dulcis and G. xanthochymus, respectively, including nine iridoid and iridoid glucosides (1-9), two dihydrochalcone dimers (10 and 11), two flavonoids and three flavonoid glycosides (12-16), two sterols (17 and 18), ten triterpenoids (19-28), five xanthones (29-33), one naphthoquinone (34), one benzenepropanamide (35), four phenylethanoid glycosides (36-39) and two other compounds (40 and 41). Among which, 15 compounds (1-4, 10-11, 14-18, 29-31 and 34) were new natural products. The results of pharmacological trails verified that littoralisone (1), gelsemiol (5), 7a-hydroxysemperoside aglucone (6), verbenachalcone (10), littorachalcone (11), stigmast-5-ene 3beta,7alpha,22alpha-triol (18), ursolic acid (19), 3beta-hydroxyurs-11-en-28,13beta-olide (24), oleanolic acid (25), 2alpha,3beta-dihydroxyolean-12-en-28-oic acid (26), 1,4,5,6-tetrahydroxy-7,8-di(3-methylbut-2-enyl)xanthone (29), 1,2,6-trihydroxy-5-methoxy-7-(3-methylbut-2-enyl)xanthone (30), 1,3,5,6-tetrahydroxy-4,7,8-tri(3-methyl-2-butenyl)xanthone (31), 12b-hydroxy-des-D-garcigerrin A (32), garciniaxanthone E (33) and (4R)-4,9-dihydroxy-8-methoxy-alpha-lapachone (34) elicited marked enhancement of NGF-mediated neurite outgrowth in PC12D cells. These substances may contribute to the basic study and the medicinal development for the neurodegenerative disorder.     

Eremophilane sesquiterpenes from Ligularia myriocephala

Five new eremophilenolides, 1beta-angeloyloxy-6beta,10beta-dihydroxy-8beta-methoxyeremophil-7(11)-en-8alpha,12-olide ( 1), 1beta-angeloyloxy-6beta,10alpha-dihydroxy-8alpha-methoxyeremophil-7(11)-en-8beta,12-olide ( 2), 1beta,6beta-diangeloyloxy-8beta,10beta-dihydroxyeremophil-(11)-en-8alpha,12-olide ( 3), 1beta,6beta-diangeloyloxy-8alpha,10 alpha-dihydroxyeremophil-7(11)-en-8beta,12-olide ( 4), 1beta-angeloyloxy-8-oxoeremophil-6,9-dien-12-oic acid methyl ester ( 5) and one known compound, 8beta,10beta-dihydroxyeremophilenolide ( 6) were isolated from the extract of the whole plant of Ligularia myriocephala Ling. Their structures and stereochemistry were elucidated by various spectroscopic methods including intensive 2D-NMR techniques (COSY, gHMQC, gHMBC and (1)H- (1)H NOESY) and HR-ESI-MS. A single-crystal X-ray experiment was performed for compound 1.     

Taxumairol M: a new bicyclic taxoid from seeds of Taxus mairei.

In addition to taxol A (1), 10-deacetyltaxol A (2), 10-deacetyl-7-epi-taxol A (3), 10-deacetylbaccatin III (5), taxuspine Z, taxezopidine G, 5 alpha-cinnamoyloxy-9 alpha,10 beta,13 alpha-triacetoxytaxa-4(20)11-diene, taxinine J, and taxinine M, a new bicyclic taxoid named taxumairol M (4), has been isolated from the seeds of Taxus mairei. The structure of 4 was determined on the basis of spectral analysis.     

New eremophilane-type sesquiterpenes from Ligularia lapathifolia

Seven new eremophilanolides were isolated from the roots and rhizomes of Ligularia lapathifolia. Their structures were established as 3beta-angeloyloxy-8beta H-eremophil-7(11)-ene-12,8alpha (14beta, 6alpha)-diolide, 3beta-angeloyloxy-8beta-hydroxyeremophil-7(11)-ene-12,8alpha(14beta,6alpha)-diolide,3beta-angeloyloxy-8beta-methoxyeremophil- 7(11)-ene-12,8alpha(14beta,6alpha)-diolide,3beta-angeloyloxy-8beta-ethoxyeremophil-7(11)-ene-12, 8alpha (14beta,6alpha)-diolide, 3beta-angeloyloxy-10beta- hydroxyeremophil-8(9),7(11)-diene-12,8(14beta,6alpha)-diolide, 3beta-angeloyloxy-8,12-expoy-12alpha-hydroxy-8beta-methoxyeremophil-7(11)-en-14beta,6alpha-olide and 3beta-angeloyloxyeremophilan-7,11-dien-14beta,6alpha-olide, by means of spectroscopic analyses. Moreover, application of a photooxygenation reaction on 7 resulted in the generation of 2 with an alpha,beta-unsaturated gamma-lactone moiety. This biomimetic transformation supports a biogenetic pathway proposed for 2.     

Two new sesquiterpene lactones from Sarcandra glabra

Two new sesquiterpene lactones (1) and (2), along with three known sesquiterpenes, atractylenolide beta (3), chloranthalactone E (4), and ( - )-istanbulin A (5), were isolated from the whole plant of Sarcandra glabra. The structures of two new compounds were established as 8beta,9alpha-dihydroxyeudesman-4(15),7(11)-dien-8alpha,12-olide (1) and 8beta,9alpha-dihydroxylindan-4(5),7 (11)-dien-8alpha,12-olide (2) on the basis of spectroscopic analysis. Compound 3 was isolated from this genus for the first time.     

Four new terpenoids from the roots of Ligularia narynensis

Four new oplopane and guaiane type sesquiterpenoids (1-3), and a monoterpenoid (4) together with three known monoterpenoids (5-7), have been isolated from the roots of Ligularia narynensis. The structures of 1-4 were elucidated as 3beta,4-diacetoxy-8alpha-(2-methylbutyryloxy)-9alpha-(4-methylsenecioyloxy)-11alpha,12-epoxyoplop-10 (14)-ene (1), 3beta,4-diacetoxy-9alpha-(4-acetoxy-4-methylsenecioyloxy)-2beta,8alpha-di (2-methylbutyryloxy)-11alpha,12-epoxyoplop-10 (14)-ene (2), 2alpha-hydroxy-1betaH,7alphaH,10alphaH-guai-4,11 (12)-dien-3-one (3) and 1alpha,2beta,3alpha,6alpha-tetrahydroxy-p-menthane (4) by spectroscopic methods. 1 and 2 were evaluated for their in vitro cytotoxic activity against cultured SMMC-7721 (human hepatoma), L02 (human hepatocyte), and HL-60 (human promyelocytic leukaemia) cell lines.     

西洋参茎叶总皂苷碱降解成分西洋参茎叶总皂苷碱降解成分

目的研究西洋参茎叶总皂苷碱降解成分。方法采用硅胶柱色谱并结合HPLC进行分离纯化，通过波谱分析鉴定化合物的结构。结果从西洋参茎叶总皂苷碱降解产物中分离得到9种成分，分别鉴定为：20(S)-原人参二醇(I)，20(S)-达玛-25(26)-烯-3β,12β,20-三醇(II)，24(R)-ocotillol (III)，20(S)-原人参三醇(IV)，20(S)-达玛-25(26)-烯-3β,6α,12β,20-四醇(V)，达玛-20(21),24-二烯-3β,12β-二醇(VI)，达玛-20(21),24-二烯-3β,6α,12β-三醇(VII)，20(S),24(S)-达玛-25(26)-烯-3β,6α,12β,20,24-五醇(VIII)，20(S)-达玛-23-烯-25-过氧羟基-3β,6α,12β,20-四醇(IX)。结论碱降解20位S构型未改变。V，VII，VIII，IX为4个新化合物，并利用2D-NMR技术对新化合物的氢和碳的化学位移进行了归属。其中I对HCT-8人结肠癌细胞具有较强的细胞毒活性。     

New eremophilenolides from Cacalia pilgeriana

Five new eremophilenolides and a known sesquiterpene were isolated from the methanol extract of the roots of Cacalia pilgeriana. Their structures were identified as 1 beta-hydroxy-2 beta-methyl-senecioyloxyeremophil-7(11)-en-8 beta(12)-olide (1), 1 beta-hydroxy-2 beta-methylsenecioyloxy-8 alpha-methoxyeremophil-7(11)-en- 8 beta(12)-olide, 2 beta-hydroxy-3 beta-methylsenecioyloxyeremophil-7(11)-en-8 alpha(12)-olide ( 3), 2 beta,8 beta-dihydroxy-3 beta-methylsenecioyloxyeremophil-7(11)-en-8 alpha(12)-olide and 1 beta,8 beta-dihydroxy-2 beta,3 alpha-diangeloyloxyeremophil-7(11)-en-8 alpha(12)-olide ( 5) and caryolane-1,9 beta-diol by spectroscopic methods including 2D-NMR techniques ( (1)H- (1)H COSY, HMQC, HMBC) and HR-ESI-MS. The structure and relative stereochemistry of compound 1 were unequivocally established by X-ray diffraction analysis. Bioassays showed compounds 3 and 5 to possess strong cytotoxic activity in vitro against human leukemia cells (HL-60) (IC (50) < 15 microg mL (-1)). The structure-activity relationship is discussed.     

New eremophilane-type sesquiterpenes from Ligularia hodgsonii

Four new eremophilanlides (1- 4) together with a known sesquiterpene were isolated from the roots and rhizomes of Ligularia hodgsonii. The structures of these new compounds were established as 6beta-(2'-methylbutanoyloxy)-10beta-acetoxy-3 beta, 8beta-dihydroxyeremophil-7(11)-en-8,12-olide (1), 6beta,10 beta-dihydroxyeremophil-7(11)-en-8alpha,12-olide (2), 3beta-acetoxy-6,9-dien-8-oxoeremophil-12-nor-11-ketone (3), and 3beta-acetoxy-6alpha, 8alpha-dihydroxyeremophil-7(11), 9-dien-8,12-olide (4) by means of mass, IR and NMR spectroscopy.     

Cytotoxic ergosterols from Paecilomyces sp. J300

Seven ergosterol derivatives (1-7) were isolated from silkworm larvae infected with Paecilomyces sp. J300. On the basis of spectroscopic means, their structures have been elucidated as 3beta,5alpha-dihydroxy-ergosta-7,22-diene (1), 5alpha,6alpha-epoxy-(22E,24R)-ergosta-8(14), 22-diene-3beta, 7alpha-diol (2), 5alpha,6alpha-epoxy-(22E,24R)-ergosta-8,22-diene-3beta,7alpha-diol (3), ergosta-4,6,8(14),22-tetraene-3-one (4), ergosterol (5), ergosterol endoperoxide (6), 3beta,5alpha-dihydroxy-6beta-methoxyergosta-7,22-diene (7). Compounds 3-7 showed moderate cytotoxicity against five tumor cells.     

Three new diterpenoids from Coleus forskohlii Briq

Three new diterpenoids, forskolin G(2), forskolin H(3), forskolin I(4), were isolated from the whole plant of the Coleus forskohlii Briq., and their structures were elucidated as 1alpha,6beta-diacetoxy-8,13-epoxylabd-14-en-11-one, 1alpha-hydroxy-6beta,7beta-diacetoxy-8,13-epoxylabd-14-en-11-one, and 1alpha,9alpha-dihydroxy-6beta,7alpha-diacetoxy-8,13-epoxylabd-14-en-11-one on the basis of spectral data.     

Efficient preparation of derivatives of resibufogenin using microbial catalytic technique

Microbial catalysis is a useful biotechnology in studies on natural products, by which a diversity of novel or active compounds can be obtained. Structural modifications of resibufogenin (1) by hydroxylases, isomerase and glucosyltransferase in Mucor subtilissimus AS 3.2454 were investigated. Eleven products were obtained, and, on the basis of their spectral data, their structures were identified as 12beta-hydroxyresibufogenin (2), 11beta-hydroxyresibufogenin (3), 16alpha-hydroxyresibufogenin (4), 12beta-hydroxy-3-epi-resibufogenin (5), 12alpha-hydroxyresibufogenin (6), 1beta,11beta-dihydroxyresibufogenin (7), 12beta,16alpha-dihydroxyresibufogenin (8), 12alpha,16alpha-dihydroxyresibufogenin (9), 7alpha-hydroxyresibufogenin (10), 1beta,12beta-dihydroxyresibufogenin (11) and resibufogenin 12-O-beta-D-glucoside (12), respectively, of which 3, 5, 7, 11 and 12 are new compounds. This microbial catalytic process was efficient for the production of derivatives of resibufogenin giving 11 products and an overall yield of 93.60%.     

土槿皮的化学成分研究(英文)

对松科Pinaceae植物金钱松Pseudolarix kaempferi Gord的干燥根皮—土槿皮的化学成分进行了研究。应用硅胶,Sephadex LH-20,MCI柱色谱以及高效液相色谱等技术进行分离纯化,利用化合物的理化常数和波谱数据鉴定其结构。分离并鉴定了26个化合物,分别为:土槿丁酸(1),土槿甲酸(2),土槿乙酸(3),土槿丙酸(4),3β-乙酰氧基-齐墩果烷-11,13(18)二烯(5),3β-乙酰氧基-齐墩果烷-9(11),12二烯(6),3β-羟基-齐墩果烷-11,13(18)二烯(7),3β-羟基-齐墩果烷-9(11),12二烯(8),Celangulatin C(9),Celangulatin E(10),17β-通关藤苷元B(11),11α-O-(2-甲基丁酰基)-12β-O-乙酰基通关藤苷元B(12),11α-O-(2-甲基丁酰基)-12β-O-巴豆酰基(顺芷酰基)通关藤苷元B(13),β-谷甾醇酯(14),伞形花内酯(15),5,7-二羟基香豆素(16),花椒毒素(17),异虎耳草素(18),芒柄花黄素(19),毛蕊异黄酮(20),Cnidimol B(21),胸腺嘧啶(22),3-呋喃甲酸(23),2-呋喃甲酸(24),香草酸(25),原儿茶酸(26)。其中化合物5–24为首次从该植物中分离得到;并首次归属化合物1的1H和13CNMR谱数据。     

Structure-activity relationship of various corticosteroids on the feedback control of corticotrophin secretion.

Several steroids occurring in the pathway of corticosteroid biosynthesis were investigated for their ability to exert a fast or delayed feedback inhibition of stress-induced release of corticotrophin. Rats were injected subcutaneously with vehicle or a steroid either 10 min (fast feedback) or 4 h (delayed feedback) before they were subjected to stress which consisted of a 2 min exposure to ether vapour. 2 Changes in plasma corticosterone concentration and in vitro corticosterone production by excised adrenal glands were used as indices of corticotrophin release. 3 Among the steroids tested only 11beta, 21-dihydroxypregn-4-ene-3, 20-dione (corticosterone) and 11beta, 17alpha, 21-trihydroxypregn-4-ene-3, 20-dione (cortisol) inhibited the stress response 10 min after their administration. Therefore, it appears that the fast feedback mechanism is limited to steroids with a 21-hydroxyl and a 11beta-hydroxyl group. 4 In contrast, many steroids caused inhibition of the stress response 4 h after their administration. These steroids were corticosterone, cortisol, 21-hydroxypregn-4-ene-3, 20-dione (11-deoxycorticosterone), 17alpha, 21-dihydroxypregn-4-ene-3, 20-dione (11-deoxycortisol), 11beta-hydroxypregn-4-ene-3, 20-dione (11beta-hydroxyprogesterone) and 11beta, 17alpha-dihydroxypregn-4-ene-3, 20-dione (11beta, 17alpha-dihydroxyprogesterone). Thus, either the 21-hydroxyl group (e.g. 11-deoxycorticosterone) or the 11beta-hydroxyl group (e.g. 11beta-hydroxyprogesterone) is sufficient for delayed feedback activity. The 11alpha-hydroxyl group, e.g. 11alpha, 17alpha, 21-trihydroxypregn-4-ene-3, 20-dione (11-epicortisol) renders the steroid inactive on both feedback mechanisms. 5 18,21-Dihydroxypregn-4-ene-3, 20-dione (18-hydroxydeoxycorticosterone) was found to be the only steroid that is secreted by the adrenal gland of the rat in quantities sufficient to cause exaggeration of the stress-induced release of corticotrophin. This steroid has been implicated as a possible hypertensive agent, and its role in the control of corticotrophin secretion is discussed here.