Two xanthones and two rotameric (3⟶8) biflavonoids from the Cameroonian medicinal plant Allanblackia floribunda Oliv. (Guttiferae)

1 Two xan hones and wo o ame ic (3⟶8) bi la onoids om he Came oonian medicinal plan Allanblackia lo ibunda Oli . (Gu i e ae) Bel Youssou G. Moun essoua,b, Joseph Tchamgouea, Jean Paul Dzoyemc, Roland T. Tchuenguemc, F ank Su upd, Muhammad I. Choudha yb, I an R. G eene, Simeon F. Kouama,* aDepa men o Chemis y, Highe Teache T aining College, Uni e si y o Yaoundé I, P.O. Box 47, Yaoundé, Came oon bH.E.J. Resea ch Ins i u e o Chemis y, In e na ional Cen e o Chemical and Biological Sciences (ICCBS), Uni e si y o Ka achi, Ka achi-75270, Pakis an cDepa men o Biochemis y, Facul y o Science, Uni e si y o Dschang, P.O. Box 67, Dschang, Came oon dDepa men o Mic obial D ugs, Helmhol z Cen e o In ec ion Resea ch and Ge man Cen e o In ec ion Resea ch, pa ne si e Hanno e /B aunschweig, Inho ens asse 7, D-31824 B aunschweig, Ge many eDepa men o Chemis y and Polyme Science, Uni e si y o S ellenbosch, P/Bag X1, Ma ieland, S ellenbosch, 7602, Sou h A ica *Co esponding au ho : Tel.: +237 694 464 535; e-mail add ess: k [email protected] (S. F. Kouam). 2 Abs ac Two xan hones, 2-(3-hyd oxy-3,3-dime hyldihyd oallyl)-dihyd o-6-deoxyisojaca eubin (1) and dihyd o-6-deoxyjaca eubin (2), and wo 3⟶8 o ame ic bi la onoids, (2R,3S)- olkensi la one-7-O-𝛽-ace ylglucopy anoside (3) and (2S,3S)-mo ello la one-7-O-𝛽- ace ylglucopy anoside (4), oge he wi h i een known compounds, we e isola ed om a dichlo ome hane/me hanol (1/1, / ) ex ac o he ba k o he plan Allanblackia lo ibunda. The s uc u es o he new compounds we e elucida ed by NMR spec oscopy and mass spec oscopic echniques and hose o he known ones we e deduced by compa ison wi h da a epo ed in he li e a u e. The isola ed bi la onoids we e ob ained as mix u es o con o me s exhibi ing duplica e NMR signals in solu ion a 25 °C and hei espec i e absolu e con igu a ions we e assigned using ci cula dich oism spec oscopy. Some o he isola ed compounds we e assessed o hei an ibac e ial and an ioxidan p ope ies. 3 1. In oduc ion Allanblackia lo ibunda Oli e belongs o he Gu i e ae amily and is widely dis ibu ed along he coas al egions o Wes A ica. In olk medicine, di e en pa s o his plan a e ei he used alone o in combina ion wi h o he plan s o he ea men o se e al human ailmen s including uppe espi a o y ac in ec ions, dysen e y, dia hoea, and oo hache.1 Biological and pha macological in es iga ions o ex ac s o his plan ha e enabled a be e unde s anding o hei use in adi ional medicine. Fo ins ance, he an i umo , adical sca enging, an imycobac e ial, an ibac e ial and an i ungal ac i i ies o he oo ba k ex ac o A. lo ibunda ha e been epo ed.2 In es iga ions o his plan ha e led o he isola ion o a se ies o seconda y me aboli es belonging o di e en classes including i e penoids,3 benzophenones,4 xan hones5 and bi la onoids.2,4 Some o hese compounds exhibi a wide ange o biological and pha macological ac i i ies including an ioxidan , an i umo ,2 cy o oxic,5 an i-in lamma o y, an imic obial and an i ungal ac i i ies,6,7 as well as HIV inhibi o y ac i i y.8 As pa o ou con inuing sea ch o biologically ac i e compounds om Came oonian medicinal plan s,9–12 we ha e in es iga ed he ba k o A. lo ibunda o i s mino seconda y me aboli es and he ein epo he isola ion, s uc u al elucida ion and biological ac i i ies o wo new xan hones (1 and 2) and wo new o ame ic bi la onoids (3 and 4). 2. Resul s and Discussion The dichlo ome hane/me hanol ex ac o he s em ba k o A. lo ibunda was subjec ed o epea ed column ch oma og aphy o gi e se e al ac ions, which we e u he pu ified o e sephadex LH–20 and p epa a i e HPLC o yield a o al o nine een compounds o which compounds 1–4 we e unknown. 4 3 OO O OH OH 2 R1R2 H 6OH 7H OH O OH O O O 16 O OH O O OH OH 1 12 3 4 4a 5 6 7 8 4b 8a 9 1' 2' 3' 4'' 5' 9a 1'' 2'' 3'' 5'' 4' TFA/ O O OH O O OH HO OH I-A I-B I-C II-D II-E II-F 1 2 3 5 6 4 71' 8 9 10 2' 3' 4' 5' 6' 1 2 3 4 5 6 78 1'' 2'' 3'' 4'' 5'' 6'' 9 10 OH OH R2 O O OH O O OH HO OH I-A I-B I-C II-D II-E II-F OH R1 O OH 2'' 4'' 5'' 6'' 8'' 7'' 1'' 3'' 4 5H OH 8 O OH OH OH OH HO 9 O O OH O O OH HO OH OH OH O HO HO OAc O OH O HO HO OH O OH O HO HO OH O OH O HO HO O O Figu e 1. Chemical s uc u es o compounds 1−9 and 16. Compound 1 was ob ained as a yellow solid (m.p. 186–187 °C), which eac ed posi i ely o FeCl3 eagen . I s molecula o mula C23H26O6 was es ablished om he posi i e ion mode HRESIMS, which showed ion clus e s [M+H]+ a m/z 399.1802 (calcd. o C23H27O6: 399.1808). The IR spec um showed s ong abso p ions o hyd oxyl and conjuga ed ca bonyl g oups a 3400 and 1640 cm–1 espec i ely, while he UV spec um exhibi ed cha ac e is ic abso p ion bands o xan hones a 𝜆max 234 and 250 nm.13 The 1H NMR spec um o compound 1 displayed an ABC spin sys em a 𝛿H 7.73 (dd, 1.8; 7.9 Hz), 7.27 (dd, 1.8; 7.9 Hz) and 7.22 (pseudo , 7.9 Hz) assignable o a 1,2,3- isubs i u ed benzene ing. The 2,2-dime hyldihyd opy an moie y was deduced om he signals a 𝛿H 2.93 and 1.76 (2H each, , 7.9 Hz) and 𝛿H 1.37 (6H, s) which was u he con i med by he 13C NMR spec um wi h esonances a 𝛿C 72.7, 41.3, 29.8 and 16.4. This 2,2-dime hyldihyd opy an g oup was a ached a C-3 and C-4 o he xan hone skele on o compound 1 as illus a ed by HMBC co ela ions (Fig. 2) obse ed be ween he me hylene p o ons a 𝛿H 2.93 (H-1ꞌ) wi h he ca bon signals a 𝛿C 158.8 (C-3); 152.0 (C-4a); 107.9 (C-4); 72.7 (C-3′) and 41.3 (C-2′). On he o he hand, he p esence o a 3-hyd oxy-3-me hylbu yl g oup was also deduced by he p esence o signals a 𝛿H 2.77 and 1.77 (2H each, , 7.0 Hz) and 1.40 5 (6H, s) which we e u he con i med in he 13C NMR spec um wi h esonances a 𝛿C 72.7, 41.3, 29.8 and 16.4 espec i ely. Thus, HMBC co ela ions be ween he me hylene p o ons a 𝛿H 2.77 (H-1ꞌꞌ) and he ca bon signals a 𝛿C 158.8 (C-3); 103.7 (C-2); 76.2 (C-3′′) and 31.7 (C-2′′) clea ly iden i ied he poin o a achmen a C-2 o he xan hone skele on. Based on he abo e in es iga ions, s uc u e 1 was named 2-(3-hyd oxy-3,3-dime hyldihyd oallyl)-dihyd o-6- deoxyisojaca eubin (Fig. 1). The p oposed s uc u e was ully suppo ed by HMBC, DEPT and COSY spec a. Key HMBC co ela ions o compounds 1 a e illus a ed in Fig. 2. Fu he mo e, compound 1 was hea ed a e lux in TFA o 30 min. The esul ing p oduc , bispy anoxan hone (16) allowed addi ional con i ma ion o he p oposed s uc u e o 1. 3 O O HO HO OH O O H3C O O OH O O OH HO OH OH H H O O O OH OH 2 OH O O O OH OH 1 Figu e 2. Key HMBC co ela ions o compounds 1–3. 6 Table 1. 13C and 1H NMR da a o compounds 1 and 16 (CDCl3) a 25 °C. C and H no. 1 16 13C (176 MHz) 1H (500 MHz) 13C (176 MHz) 1H (700 MHz) 𝛿C (𝑚) 𝛿H (𝑛H, J in Hz) 𝛿C (m) 𝛿H (𝑛H, J in Hz) 1 158.2 (C) - 154.2 (C) - 2 103.7 (C) 6.19 (1H, s) 105.8 (C) 6.19 (1H, s) 3 158.8 (C) - 157.8 (C) - 4 107.9 (C) - 99.6 (C) - 4a 152.0 (C) - 153.9 (C) - 4b 144.6 (C) - 143.5 (C) - 5 145.5 (C) - 144.1 (C) - 6 119.9 (CH) 7.27 (dd, 1.8; 7.9) 119.0 (CH) 7.28 (1H, dd, 1.5, 8.0) 7 123.6 (CH) 7.22 (pseudo , 7.9) 123.8 (CH) 7.23 (1H, pseudo , 8.0) 8 116.0 (CH) 7.73 (dd, 1.8; 7.9) 117.9 (CH) 7.64 (1H, dd, 1.5, 8.0) 8a 121.0 (C) - 106.2 (C) - 9 181.3 (C) - 176.1 (C) - 9a 102.6 (C) - 102.0 (C) - 1 16.4 (CH2) 2.93 (2H, , 7.9) 16.7 (CH2) 2.93 (2H, , 6.7) 2 41.3 (CH2) 1.76 (2H, , 7.9) 31.7 (CH2) 1.93 (2H, , 6.7) 3 72.7 (C) - 76.3 (C) - 4 29.8 (CH3) 1.37 (3H, s) 26.9 (CH3) 1.42 (3H, s) 5 29.8 (CH3) 1.37 (3H, s) 26.9 (CH3) 1.42 (3H, s) 1 16.2 (CH2) 2.77 (2H, , 7.0) 17.0 (CH2) 2.65 (2H, , 6.7) 2 31.7 (CH2) 1.87 (2H, , 7.0) 31.5 (CH2) 1.84 (2H, , 6.7) 3 76.2 (C) - 76.0 (C) - 4 26.9 (CH3) 1.40 (3H, s) 26.6 (CH3) 1.45 (3H, s) 5 26.9 (CH3) 1.40 (3H, s) 26.6 (CH3) 1.45 (3H, s) 7 Compound 2, named dihyd o-6-deoxyjaca eubin, was ob ained as an o ange solid (m.p. 190–192 °C) which also eac ed posi i ely o FeCl3 eagen . I s molecula o mula C18H16O5 was es ablished om he posi i e ion mode HRESIMS, which showed ion clus e s [M+H]+ a m/z 313.1072 (calcd. o C18H17O5: 313.1076). The IR spec um showed s ong abso p ions o hyd oxyl and conjuga ed ca bonyl g oups a 3400 and 1640 cm–1 espec i ely, while he UV spec um exhibi ed abso p ion maxima cha ac e is ic o xan hones a 𝜆max 234 and 250 nm.13 The 1H and 13C NMR spec a o compound 2 showed simila i ies wi h hose o compound 1 and addi ionally displayed wo me hylene signals a 𝛿H 2.75 and 1.87 (2H each, , 6.7 Hz) oge he wi h a 6-p o on single a 𝛿H 1.40 sugges ing he p esence o a 2,2-dime hyldihyd opy an moie y. Fu he mo e, an ABC spin sys em a 𝛿H 7.78 (1H, dd, 1.5; 8.0 Hz), 7.32 (dd, 1.5; 8.0 Hz) and 7.25 (pseudo , 8.0 Hz) was sugges i e o a 1,2,3- isubs i u ed benzene ing. The 13C NMR spec um o 2 displayed 18 ca bon signals which we e assigned in combina ion wi h DEPT and HSQC expe imen s o wo me hyls, wo me hylenes, ou me hines and en qua e na y ca bons, including a ca bonyl signal a 𝛿C 180.7 ppm. The p esence o a 2,2-dime hyldihyd opy an moie y was u he con i med by signals in he 13C NMR spec um a 𝛿C 76.6 (C-3), 31.7 (C-2), 26.8 (C-4/C-5) and 16.0 (C-1). The HMBC spec um p o ed pi o al in o de o a ach his 2,2- dime hyldihyd opy an moie y o he xan hone skele on. Thus, co ela ions be ween he me hylene p o ons a 𝛿H 2.75 (H-1′) wi h he ca bon signals a 𝛿C 160.9 (C-1); 102.6 (C-9a); 76.6 (C-3′) and 31.7 (C-2′) sugges ed ha C-1′ (𝛿C 16.0) was a ached o C-2 (𝛿C 104.6) o he xan hone skele on. In addi ion, co ela ions o he a oma ic p o on signal a 𝛿H 6.38 (1H, s, H-4) wi h ca bon signals a 𝛿C 161.8 (C-3); 154.7 (C-4a); 104.6 (C-2) and 102.6 (C-9a) we e also c ucial in con i ming he 2,2-dime hyldihyd opy an moie y being a ached a posi ions 2 and 3 o he xan hone skele on. Mo eo e , he posi ion o he chela ed hyd oxyl (𝛿H 13.22) g oup a C-5 was assigned based on he co ela ions obse ed be ween he a oma ic p o on a 𝛿H 7.78 (1H, dd, 1.5; 8.0, H-8) wi h he ca bonyl g oup signal a 𝛿C 180.7. The p oposed s uc u e o compound 2 (Fig. 2) was ully suppo ed by HMBC, DEPT and COSY spec a. I s physical and spec oscopic da a we e consis en wi h hose o a known syn he ic compound.14 To he bes o ou knowledge, compound 2 is he ein epo ed o he i s ime om a na u al sou ce. 8 Table 2. 13C and 1H NMR da a o compound 2 (CDCl3) a 25 °C. C and H no. 13C (176 MHz) 1H (500 MHz) 𝛿C (m) 𝛿H (𝑛H, J in Hz) 1 160.9 (C) - 2 104.6 (C) - 3 161.8 (C) - 4 94.9 (CH) 6.38 (1H, s) 4a 154.7 (C) - 4b 144.1 (C) - 5 144.2 (C) - 6 119.9 (CH) 7.32 (1H, dd, 1.5, 8.0) 7 123.7 (CH) 7.25 (1H, pseudo , 8.0) 8 116.9 (CH) 7.78 (1H, dd, 1.5, 8.0) 8a 121.1 (C) - 9 180.7 (C) - 9a 102.6 (C) - 1′ 16.0 (CH2) 2.75 (2H, , 6.7) 2′ 31.7 (CH2) 1.87 (2H, , 6.7) 3′ 79.6 (C) - 4′ 26.8 (CH3) 1.40 (3H, s) 5′ 26.8 (CH3) 1.40 (3H, s) Compound 3 was ob ained as a yellow solid, and had he molecula o mula C38H32O16 as es ablished om low esolu ion FAB-MS (nega i e mode) and HRFAB-MS (posi i e mode) echniques in which he molecula ions appea ed a m/z 743.3 [M–H]+ and 745.1781 [M+H]+ (calcd. o C38H33O16: 745.1769), espec i ely. The IR spec um o compound 3 showed s ong abso p ion bands a ound 3400 and 1700 cm–1 indica ing he p esence o hyd oxyl and ca bonyl g oups, espec i ely. Al hough he p ep. HPLC and LC-MS ch oma og ams indica ed his compound o be pu e, bo h i s 1H and 13C NMR spec a exhibi ed doubled se s o signals, sugges ing he p esence o wo con o me s. The 1H NMR spec um displayed cha ac e is ic signals o a suga moie y (ace ylglucopy anosyl) wi h he anome ic p o on signal a 𝛿H 5.24 (H- 1‴) and a mul iple o non-anome ic p o ons in he up ield egion (𝛿H 3.70–3.48) along wi h a wo-p o on iple o an oxyme hylene en i y a 𝛿H 4.36 ppm. The 13C NMR spec um displayed signals o 38 ca bons, which we e so ed by DEPT and HSQC echniques in o one me hyl, one me hylene, nine een me hines and se en een qua e na y ca bons, including signals o h ee ca bonyls a 𝛿C 172.6, 184.0 and 197.3 ppm (Table 4). Compounds wi h simila spec al da a 9 ha e been p e iously epo ed om he plan s o he genus Ga cinia o he Gu i e ae amily.15– 18 The e o e, compa ison o he spec oscopic da a o compound 3 wi h hose desc ibed in he li e a u e enabled us o deduce ha i was a monoglycosyla ed bi la onoid de i a i e p esen ing doubled NMR signals. I is no ewo hy ha he doubled signals in he NMR spec a o bi la onoids a oom empe a u e may be due o he ac ha he molecules adop di e en con o ma ions16 which a ise om he es ic ed ee o a ion o he 3→8 in e la anyl bond.17 Ne e heless, hese NMR signals can be me ged in o a single se o signals a highe empe a u es because unde hese condi ions, he molecules do no exis in a p e e ed s able con o ma ion.19 Howe e , he s uc u al elucida ion o compound 3 based on i s NMR da a eco ded a ambien empe a u e was no s aigh o wa d. In he 1H NMR spec um, excep o a pai o double s a 𝛿H 5.96 and 5.97 (1H each, d, 1.6 Hz, H-6, H-8) assignable o wo me a-coupled p o ons o ing I-A o he la anone moie y o bo h he majo and mino con o me s, he 1H NMR esonances o he majo con o me we e mos ly obse ed in he deshielded a oma ic egion (𝛿H 6.40–7.80) whe eas, signals appea ing in he up- ield egions we e assigned o he suga moie y. The 1H NMR spec um o compound 3 also displayed cha ac e is ic signals o la ones a 𝛿H 6.45 (1H, s, H-II-3) and 𝛿H 5.71 and 5.33 (1H each, d, 12.0 Hz, H-I-2, H-I-3) indica ing he p esence o bo h moie ies in he molecule. The coupling cons an o 12.0 Hz indica es a biaxial ( ans) con igu a ion o he wo p o ons o ing I-C. In addi ion, cha ac e is ic signals o wo sepa a e AA'BB' sys ems we e obse ed a 𝛿H 7.73 and 6.91 (2H each, d, 8.8 Hz, H-3″/5″, H-2″/6″) o one sys em and 𝛿H 7.02 and 6.34 (2H each, d, 8.4 Hz, H-2′/6′, H-3′/5′) assignable o he wo 1,4-disubs i u ed a oma ic ing sys ems o he la one ( ing II-E) and la anone ( ing I-B) moie y, espec i ely. The co ela ions o hese se s o p o ons iz. H-2″/6″ wi h H-3″/5″and H-2′/6′wi h H-3′/5′ we e ully suppo ed by hei 1H–1H COSY co ela ions (see ESI) bo h o he majo and he mino con o me s. A one p o on single assignable o H-6 o each o he la one uni s was e iden in he 1H NMR spec um. In e es ingly, signals a ibu able o an ace yl g oup we e obse ed in he 1H and 13C NMR spec a a 𝛿H/C 1.95/20.7 (CH3) and 172.7 (CH3C=O). The comple e assignmen o he wo con o me s o compound 3, as p esen ed in Tables 3 and 4 espec i ely, was acili a ed by he HSQC and HMBC spec a. The ace ylglucopy anosyl moie y was linked a posi ion C-7 o he la one uni and deduced by co ela ions obse ed in he HMBC spec um be ween he anome ic p o on a 𝛿H 5.24 wi h ca bon signals a 𝛿C 161.6 (C-7) and 𝛿C 100.0 (C-6) o ing D (Fig. 2). 16 Silica gel 60 (0.230–0.400 mm) and (0.040–0.063 mm) was used as adso ben s o lash and column ch oma og aphy espec i ely. The semi-pu e compounds we e inally pu i ied successi ely o e Sephadex LH-20 (bead size 25–100 μm, Sigma-Ald ich) wi h CH2Cl2–MeOH (1/1, / ), e e se (JAIGEL–ODS H80, se ial no. 209963) and no mal (JAIGEL–SIL, D-60-10, se ial no. 051300228) phase p epa a i e HPLC. The speci ica ions o hese columns we e 250 mm leng h×20 mm inne diame e ; 4𝜇m pa icle size and 80 Å po e size. Me ck TLC pla es (silica gel 60 F254) we e used o he de ec ion o he pu i y o compounds. Mel ing poin s we e de e mined wi h Gallekamp appa a us. UV spec a we e eco ded using a Pe kinElme Lambda 25 UV/Vis spec ome e . IR spec a we e eco ded in KB on a Pe kinElme 2000 FT-IR spec opho ome e . EI/ESI mass spec a we e eco ded on an Agilen 5975C MSD and The mo Finnigan MAT95XL mass spec ome e s a he Hussein Eb ahim Jamal Resea ch Ins i u e o Chemis y (HEJ–RIC) o he In e na ional Cen e o Chemical and Biological Sciences (ICCBS), Uni e si y o Ka achi (UOK), Ka achi Pakis an. The NMR expe imen s o pu e compounds we e pe o med in di e en deu e a ed sol en s depending on hei solubili y, using B uke Ascend 400, 500 and 600 MHz (1H and 13C) spec ome e s equipped wi h a B uke 5 mm B oadband p obe (depending on he amoun ). Chemical shi s (𝛿) in ppm a e e e enced o e ame hylsilane (TMS) a 0.00 ppm o 1H and 13C. Coupling cons an s a e exp essed in he z (Hz). 4.2. Plan ma e ial The s em ba k o A. lo ibunda Oli e was collec ed in No embe 2014 in he Kye-Ossi, N em alley Di ision in he Sou h egion o Came oon. The sample was iden i ied by M . Vic o Nana, a e i ed bo anis a he Na ional He ba ium o Came oun, Cen e egion, whe e a ouche specimen was deposi ed as ouche No: 52904/HNC. 4.3. Ex ac ion and isola ion The ai -d ied and g ound s em ba k (2.2 kg) o A. lo ibunda was ex ac ed a oom empe a u e wi h a mix u e o CH2Cl2/MeOH (1/1, / ) o 48 h and concen a ed o a iscous black esidue (556 g). A pa o his esidue (550.0 g) was hen subjec ed o lash ch oma og aphic sepa a ion o e a silica gel (230–400 mesh) column using a s epwise g adien o 𝑛-Hex/E OAc ( anging om 0 o 100% o E OAc, / ), ollowed by a g adien o E OAc/MeOH ( anging om 9/1 o 8/2, / ), o a o d a o al o 58 ac ions (𝑓 1–𝑓 58) o ca. 17 1000 mL pe ac ion. F ac ion 𝑓 15 (elu ed wi h 𝑛-Hex/E OAc 9/1) p ecipi a ed o gi e compound 10 (100 mg, yellow solid). Fu he p ecipi a ion o he emaining aliquo o his same ac ion ga e an insepa able mix u e o phy os e ols (180 mg, whi e powde ). F ac ion 𝑓 22 (𝑛- Hex/E OAc 8/2, / ) p ecipi a ed o a o d compound 12 (6 mg, yellow solid). F ac ions 𝑓 48, 𝑓 50, 𝑓 51 and 𝑓 53 ob ained wi h pu e E OAc, we e mass-p ecipi a ed o gi e ou di e en yellow amo phous powde s labelled Y5 (0.5 g), Y6 (3.4 g), Y7 (2.1 g) and Y8 (0.4 g) espec i ely. All ou impu e powde s we e subsequen ly sepa a ely pu i ied o e e e se phase p epa a i e HPLC (column JAIGEL–ODS H80) using a mix u e o ace oni ile/wa e : 1/1 + 0.08% o TFA as eluen , wi h he ollowing se ings: UV sensi i i y 0.05; RI sensi i i y 50; ini ial & inal low a es: 3 & 4 mL/min; ini ial & inal p essu es: 47 & 64 psi. Consequen ly, compounds 5 (75 mg), 6 (100 mg), 7 (25 mg) and 8 (105 mg) we e elu ed wi h e en ion imes o 22, 18, 14 and 12 min espec i ely. All 58 ac ions (𝑓 1–𝑓 58) om he lash ch oma og aphy we e combined in o 4 main ac ions (A–D) on he basis o hei TLC analyses. F ac ion A (𝑓 1–𝑓 7: 850 mg) ob ained wi h pu e 𝑛-Hex as eluen , consis ed o a y acids and was no in es iga ed u he . F ac ion B (𝑓 8–𝑓 33: 38.7 g) ob ained wi h 𝑛-Hex/E OAc (8/2–4/6, / ), was subjec ed o u he column ch oma og aphy o e silica gel (0.040–0.063 mm) and elu ed wi h a g adien o 𝑛-Hex/E OAc (9.5/0.5–0/10, / ) o p oduce 100 ac ions (B1–B100) o ca. 500 mL each which we e combined on he basis o TLC analysis. The i s 28 ac ions om ac ion B (B1–B28), we e elu ed wi h a mix u e o 𝑛-Hex/E OAc (9.5/0.5, / ) and combined on he basis o hei TLC p o iles in o wo sub- ac ions. The i s sub- ac ion b15–b20 (200 mg) was ech oma og aphed o e Sephadex LH-20 (CH2Cl2/MeOH (1/1, / ) and hen o e no mal phase p ep. HPLC, using an isoc a ic mode sol en o 𝑛-Hex/E OAc (8.8/1.2, / ), o a o d compound 14 (2.5 mg, o ange oil) wi h a e en ion ime o 44 min. The second sub- ac ion b21–b28 (150 mg) showed a complex mix u e o oils and was no u he in es iga ed. The second se ies o ac ions om ac ion B (B29-B40) was elu ed wi h 𝑛-Hex/E OAc (9/1, / ) and combined, hen was u he ch oma og aphed and elu ed on no mal phase p epa a i e HPLC, using an isoc a ic mode o sol en 𝑛-Hex/E OAc (8.5/1.5, / ) o a o d compound 2 (0.7 mg, o ange solid), a a e en ion ime o 20 min. The hi d se ies o ac ions om ac ion B (B41-B43) (30 mg) was elu ed wi h 𝑛-Hex/E OAc (8/2, / ), hen ech oma og aphed and elu ed on no mal phase p epa a i e HPLC, using an isoc a ic mode o sol en 𝑛-Hex/E OAc (7/3, / ) o a o d compound 1 (12 mg, yellow solid), a a e en ion ime o 25 min. The ou h se ies o ac ions om ac ion B (B44-B45) (88 mg) was 18 ech oma og aphed o e Sephadex LH-20 (CH2Cl2/MeOH (1/1, / ), o a o d compound 11 (18 mg, yellow solid). The i h se ies o ac ions om ac ion B (B52–B59) (10 mg) was u he ch oma og aphed and elu ed on no mal phase p epa a i e HPLC, using an isoc a ic mode o sol en 𝑛-Hex/E OAc (7.5/2.5, / ) o a o d compound 13 (1.8 mg, yellow solid), a a e en ion ime o 44 min. F om he six h se ies o ac ions om ac ion B (B60–B77), a whi e solid compound 15 (60 mg, whi e nea solid) was ob ained. The las se ies o ac ions ob ained om ac ion B (B78–B100) elu ed wi h 𝑛-Hex/E OAc (7/3–2/8, / ) was ound o be a complex mix u e o compounds and was no u he in es iga ed. F ac ion C (𝑓 34–𝑓 57: 137 g), elu ed wi h 𝑛-Hex/E OAc 3/7–1/9, / ) om he lash ch oma og aphy was shown o con ain he al eady pu i ied compounds 5; 6 and 8 and he e o e was no u he in es iga ed. A pa o ac ion D (𝑓 58: 80 g; pu e E OAc) was subjec ed o u he ch oma og aphic sepa a ions o e sephadex LH-20 using CH2Cl2/MeOH (1/1) as eluen o a o d eigh een sub- ac ions (D1–D18). Sub- ac ion D9 (1.8 g) was subjec ed o silica gel column ch oma og aphy and elu ed wi h an isoc a ic sys em o 𝑛-Hex/E OAc (6/4, / ) o a o d a mix u e o glycosyla ed s e ols (105 mg). Sub- ac ions D5 (150 mg), D16 (200 mg) and D17 (300 mg) we e sepa a ely pu i ied on a e e se phase p ep. HPLC using isoc a ic sol en s o a o d compounds 9 (5 mg, o ange oil), 3 (15 mg, yellow solid), and 4 (18.8 mg, yellow solid) espec i ely. 4.3.1. 2-(3-hyd oxy-3,3-dime hyldihyd oallyl)-dihyd o-6-deoxyisojaca eubin (1). Yellow solid om Hex/E OAc 7/3, m.p. 186–187 °C; UV (MeOH) – 𝜆max nm (PDA): 234, 250, 269, 330 nm; HRESIMS m/z 399.1802 (calcd. o C23H27O6: 399.1808). Fo 1H and 13C NMR da a, see Table 1. 4.3.2. dihyd o-6-deoxyjaca eubin (2). O ange solid om Hex/E OAc 8.5/1.5, m.p. 190–192 °C; UV (MeOH) – 𝜆max nm (PDA): 234, 250, 269, 330 nm; HRESIMS [M+H]+ a m/z 313.1072 (calcd. o C18H17O5: 313.1076). Fo 1H and 13C NMR da a, see Table 2. 4.3.3. (2R,3S)- olkensi la one-7-O-𝛽-ace ylglucopy anoside (3). Yellow solid om E OAc ac ion; m.p. 241–243 °C; [𝛼]25D = 0° (c = 0.067, MeOH); UV (MeOH) – 𝜆max nm (log ℰ): 229 (3.91), 292 (3.80), 324 (3.73); IR (KB ): 𝜈max = 3418, 2927, 1728, 1645, 1604, 1510, 1451, 1370, 1243, 1172, 1082, 834, 742, 622, 526 cm–1; HRFESIMS m/z 745.1781 [M+H]+ (calcd. o C38H33O16: 745.1769). Fo 1H and 13C NMR da a, see Tables 3 & 4. 19 4.3.4. (2S,3S)-mo ello la one-7-O-𝛽-ace ylglucopy anoside (4). Yellow solid om E OAc; m.p. 245–247 °C; [𝛼]20D = 0° (c = 0.046, MeOH); UV (MeOH) – 𝜆max nm (log ℰ): 222 (4.31), 230 (4.39), 287 (4.36), 291 (4.36), 344 (4.18); IR (KB ): 𝜈max = 3384, 1726, 1643, 1603, 1515, 1452, 1369, 1262, 1169, 1082, 834, 741, 630, 559, 526 cm–1; HRESIMS m/z 761.1732 [M+H]+ (calcd. o C38H33O17: 761.1718). Fo 1H and 13C NMR da a, see Tables 3 and 4. 4.3.5. Con e sion o (1) o (16) Compound 1 (10 mg) was dissol ed in i luo oace ic acid (2 mL) and was hea ed unde e lux o 30 min. The esul ing mix u e was sepa a ed and pu i ied by p ep. HPLC wi h 𝑛- Hex/E OAc (7/3, / ) o a o d compound 16 (7.4 mg, 74%), a a e en ion ime o 22 min. Compound 16 was ob ained as a pale yellow oil and iden i ied as 1,5-dihyd oxy-1,2,3,4-bis(2,2- dime hyldihyd opy ano)xan hone. HRESIMS [M+H]+ a m/z 381.1702 (calcd. o C23H25O5: 381.1702). Fo 1H and 13C NMR da a, see Table 1. 4.3.6. Assays o an ibac e ial and an ioxidan ac i i ies The an ibac e ial ac i i y was e alua ed using he b o h mic odilu ion me hod by de e mining he minimum inhibi o y concen a ion (MIC) alues agains he i e bac e ia s ains iz., Esche ichia coli (ATCC 25922); Pseudomonas ae uginosa (ATCC 27853); S aphylococcus au eus (ATCC BAA1026); En e ococcus aecalis (ATCC 29212); P o eus mi abilis (isola e). The an ioxidan capaci y o he compounds was e alua ed based on he p inciple o sca enging he DPPH (2,2-diphenyl-1-pic ylhyd azyl) adical. Acknowledgemen s BYGM is g a e ul o The Wo ld Academy o Sciences (TWAS) o an eigh -mon h ellowship unde he auspices o he ICCBS-TWAS p og amme o wo k a he H.E.J. Resea ch Ins i u e o Chemis y, Uni e si y o Ka achi, Ka achi-75270, Pakis an. This s udy was also suppo ed by he Alexande on Humbold Founda ion and he Ge man Academic Exchange Se ice (DAAD) h ough he equipmen subsidies o SFK. Con lic o In e es The au ho s decla e no con lic o in e es . 20 Re e ences and no es 1. Raponda-Walke , A.; and Sillans, R. "Les Plan es U iles du Gabon". Paul Leche alie , 1961, Pa is VI. 2. Kue e, V.; Azebaze, A.G.; Mba eng, A.; Nguem o, E.L.; Tshikalange, E.T.; Chala d P.; and Nkeng ack, A.E. Pha m. Biol. 2011, 49, 57–65. 3. Azebaze, A.G.B.; Ouahouo, B.M.W.; Va damides, J.C.; Valen in, A.; Kue e, V.; Acebe L.; Beng, V.P.; Nkeng ack, A.E.; and Meye , M. Na . p od. Res. 2008, 22, 333–341. 4. Locksley, H.D.; and Mu ay, I.G. J. Chem. Soc. 1971, 1332–1340. 5. Nkeng ack, A.E.; Azebaze, G.A.; Va damides, J.C.; Fomum, Z.T.; and an Hee den, F.R. Phy ochemis y 2002, 60, 381–384. 6. Nagem, T.J.; and Pe es V. Phy ochemis y 1997, 44, 199–214. 7. Pe es, V.; Nagem, T.J.; and de Oli ei a, F.F. Phy ochemis y 2000, 55, 683–710. 8. Blun , J.W.; Boswell, J.L.; Boyd M.; Ca dellina, II. J.H.; and Fulle R.W. J. Na . P od. 1999, 62, 130–132. 9. Kouam, S.F.; Yapna, D.B.; K ohn, K.; Ngadjui, B.T.; Ngoupayo, J.; Choudha y, M.I.; and Schulz, B. J. Na . P od. 2007, 70, 600−603. 10. Kouam, S.F.; Njonkou, Y.L.N.; Kuigoua, G.M.; Ngadjui, B.T.; G een, I.R.; Schulz, B.; and K ohn, K. Phy ochem. Le . 2010, 3, 185–189. 11. Tchamgoue, J.; Ha izu , M.R.; Tchouankeu, J.C.; Kouam, F.S.; Adhika i, A.; Hameed, A.; G een, R.I.; and Choudha y, M.I. Phy ochem Le . 2016, 17, 181–186. 12. Happi, M.G.; Kouam, S.F.; Talon si, F.M.; Ha mu , L.; Zühlke, S.; Ngadjui, T.B.; and Spi elle , M. Fi o e apia 2018, 124, 17−22. 13. Ngouela, S.; Zele ack, F.; Len a, B.N.; Ngouamegne, E.T.; Tchamo, D.N.; Tsamo, E.; and Connolly, J.D. Na P od Res. 2005, 19, 685–688. 14. Locksley, H. D.; Quillinan, A. J.; and Scheinmann, F. J. Chem. Soc. 1971, 3804–38140. 15. Muha ni; El i a; and Amanda. Indo J. Chem. 2011, 11, 169–173. 16. Messi, B.B.; Ndjoko-Iose , K.; He lein-Amslinge , B.; Lannang, M.A.; Nkeng ack, A.E.; Wol ende , J.-L.; Hos e mann, K.; and B ingmann G. Molecules 2012, 17, 6114-6125. 17. Jamila N.; Khai uddean M.; Khan S.N.; and Khan N. Magn. Reson. Chem. 2014, 52, 345– 352. 21 18. I o, T.; Yoko a, R.; Wa a ai, T.; Mo i, K.; Oyama, M.; Nagasawa, H.; Ma suda, H.; and Iinuma, M. Chem. Pha m. Bull. 2013, 61, 551–558. 19. Li, X-C.; Joshi, A.S.; Tan, B.; ElSohly, H.N.; Walke , L.A.; Zjawiony, J.K.; and Fe ei a, D. Te ahed on 2002, 58, 8709–8717. 20. Ha ano, T.; and Hemingway, R.W. J. Chem. Soc. Pe kin T ans. 1997, 2, 1035–1043. 21. Ga ield, W. Te ahed on 1970, 26, 4093–4108. 22. Hosoi, S.; Shimizu, E.; Ohno, K.; Yokosawa, R.; Kuninaga, S.; Coskun, M.; and Sakushima, A. Phy ochem. Anal. 2006, 17, 20–24. 24. He bin, G.A.; Jackson, B.; Locksley, H.D.; Scheinmaim F.; and Wols enholme, W.A. Phy ochemis y 1970, 9, 221. 25. Joshi, B.S.; Kama , V. N.; and Viswana han, N. Phy ochemis y 1970, 9, 881–888. 26. Sukpondma, Y.; Rukachaisi ikul, V.; and Phongpaichi , S. J. Na . P od. 2005, 68, 1010– 1017. 27. Hu adilok-Towa ana, N.; Kongkachuay, S.; and Mahabusa akam, W. Na . P od. Res., 2007, 21, 655–662. 28. Jin, W.; and Tu, P.-F. J. Ch oma og . 2005, 1019, 241. 29. Azebaze, A.G.B.; Teinkela, J.E.M.; Nguem o, E.L.; Valen in, A.; Dongmo, A.B.; and Va damides, J.C. A i Heal h Sci. 2015, 15, 835–40. 30. Okoli, B.J.; Ndukwe, G.I.; Habila, J.D.; Lawson, L.; and Jummai, A.T. In . J. Chem. S . 2016, 4, 55–62. 31. Luha a, L.P.; and Munkombwe, N.M. JIPBS. 2015, 2, 88–95. 32. Fouo sa, H.; Lannang, A.M.; Dzoyem, J.P.; Ta simo, S.J.; Neumann, B.; Mbazoa C.D.; Razaka i ony, A.A.; Nkeng ack, A.E.; Elo , J.N.; and Sewald N. Plan a Med. 2015, 81, 594– 599. 33. Pie a P.G. J. Na . P od. 2000, 63, 1035–1042.